MOLECULAR SPECTROSCOPY WITH LASER FREQUENCY COMBS
|
|
- Vanessa Franklin
- 7 years ago
- Views:
Transcription
1 MOLECULAR SPECTROSCOPY WITH LASER FREQUENCY COMBS NATHALIE PICQUÉ 1,2,3 and THEODOR W. HÄNSCH 1,2 1. Max Planck Institut für Quantenoptik, Hans-Kopfermann-Str. 1, Garching, Germany 2. Ludwig-Maximilians-Universität München, Fakultät für Physik, Schellingstrasse 4/III, München, Germany 3. Institut des Sciences Moléculaires d Orsay, C.N.R.S, Bâtiment 350, Université Paris-Sud, Orsay, France Abstract The millions of precisely controlled laser comb lines produced with a train of ultrashort laser pulses can harnessed for highly-multiplexed molecular spectroscopy. Dual-comb spectroscopy is emerging as a powerful new tool. Proof-of-principle experiments already report a million-fold improvement in the recording time, the resolution and the sensitivity of broad spectral bandwidth linear absorption spectroscopy. 1 Introduction Introduced in the late 1990s, laser frequency combs [1,2] have revolutionized precise measurements of frequency and time. The regular pulse train of a mode-locked femtosecond laser can give rise to a regular comb spectrum of millions of laser modes with a spacing precisely equal to the pulse repetition frequency. Optical frequency combs have enabled the development of new ultra-precise optical atomic clocks and commercially available combs have quickly matured to routine instruments for precise optical spectroscopy. Frequency combs are now becoming enabling tools for an increasing number of applications, from the calibration of astronomical spectrographs to molecular spectroscopy. The broad spectral bandwidth and the high-resolution structure of a frequency comb indeed make it an attractive tool for broadband direct absorption molecular spectroscopy and fingerprinting. As for precision spectroscopy of simple atomic systems, in molecular spectroscopy the comb may serve as a frequency ruler against which the frequency of a continuous-wave laser used to probe the sample is calibrated. However in recent years, novel techniques have been developed in which the comb directly interrogates the sample. Direct absorption frequency comb spectroscopy results in short measurement time and high accuracy over a broad spectral bandwidth. Such advances have been demonstrated with Michelson-based Fourier transform (FT) [3-6], dispersive [7-10] and dual-comb based Fourier transform spectrometers [11-21]. Michelson-based Fourier spectrometers record the 1
2 spectroscopic signal on a single photodetector and therefore present the advantage of an almost unlimited spectral span in any spectral region with Doppler limited resolution. The moving mirror of such scanning time-domain interferometers however inherently limits the measurement time and resolution. The sensitivity for weak absorption may additionally be significantly improved with the coherent coupling of a laser frequency comb to a high finesse-cavity containing the sample. Cavity-enhanced and cavity-ring-down spectroscopies are widely used for ultrasensitive spectroscopic absorption measurements and they have led for long to remarkable progress [22] in fundamental spectroscopy and non-intrusive trace-gas sensing when practiced with tunable narrow bandwidth lasers. In one approach to cavity-enhanced frequency comb spectroscopy, the spectral analysis of the light transmitted through the cavity is performed with a dispersive spectrometer, usually equipped with a detector array. This results [8] in the massively parallel recording of spectra typically spanning 10 nm with GHz resolution and ms acquisition time. Although dispersive spectrometers do not generally allow to directly resolve the comb lines in a motionless short measurement, scanning [9] the comb and cavity modes and implementing Vernier techniques [10] proved successful in improving the resolution, at the price of longer and sequential recordings. However, large detector arrays are not conveniently available in the mid-infrared molecular fingerprint spectral region, where most molecules have intense rovibrational signatures. Recent experiments of multi-heterodyne frequency comb Fourier transform spectroscopy (also called dual-comb spectroscopy) have demonstrated that the precisely spaced spectral lines of a laser frequency comb can be harnessed for the rapid and sensitive acquisition of highly multiplexed spectra of molecules. This approach to frequency comb spectroscopy can work in any spectral region because it uses a single photodetector, and it provides extremely short measurement times. This article discusses some of the distinguishing features of dual-comb spectroscopy. 1 Dual comb spectroscopy principle In a typical implementation of dual-comb spectroscopy (Fig. 1), an absorbing sample is interrogated by a frequency comb laser source. The information encoded by this interrogating comb needs then to be retrieved by a spectrometer. This is achieved by heterodyning the interrogating comb with a second comb, which serves as a reference. It provides simultaneous and accurate access to a broad spectral bandwidth within a short measurement time and can physically be equally understood in terms of time domain interference, multi-heterodyne detection, optical free induction decay, linear optical sampling or cross-correlation between two electric fields. In practice, the light transmitted by the sample is superimposed on a second frequency comb with slightly different repetition frequency. A single fast photodetector then produces an output signal with a comb of radio frequencies due to interference between pairs of optical comb lines. In the frequency domain (Fig.2a), the optical spectrum is thus effectively mapped into the radio frequency region, where it becomes accessible to fast digital signal processing. In the time domain (Fig. 2b), the pulse train of the interrogating comb excites the absorbing sample at regular time intervals. A second pulse train of different repetition frequency 2
3 Figure 1: Two frequency combs, 1 and 2, have slightly different line spacing. One of these combs, 1, is transmitted through the cell and heterodyned against the second comb, yielding a down-converted radio-frequency comb containing information on the absorption and dispersion experienced by each line of the comb 1. Other implementations allow the two combs to interrogate the sample. a) b) Figure 2: Physical principle of dual-comb spectroscopy. The repetition frequency of the two lasers is respectively f r1 and f r2 and they differ by Δf r<< f r1 The technique requires to keep constant the differences f r1- f r2 and f 01- f 02 during the measurement or to monitor their variations so to make a posteriori corrections a) In the frequency domain, the reference comb 2 with f r2 line spacing acts as a highly multiplexed heterodyne receiver to generate a radio-frequency comb b) In the time domain, the reference comb FC2 pulse train slowly walks through the interrogating pulses from FC1 to generate a measurement I(t) of the interrogating electric field. 3
4 samples the transient response or free induction decay of the medium, akin to an optical sampling oscilloscope. Here the phase correlations between successive laser pulses are crucial for reproducible sampling, even if the free induction decay happens on a time scale that is short compared to the time interval between two laser pulses. The first low-resolution proof-of-principle experiment was performed [16] in 2004 with unstabilized mode-locked lasers and a few groups have been contributing [11-21] since in the THz, infrared or visible regions. These firsts implementations have demonstrated a very intriguing potential of dual-comb spectroscopy without moving parts for ultra-rapid and ultra-sensitive recording of complex molecular spectra [11]. Compared to conventional Michelson-based Fourier transform spectroscopy, recording times could be shortened from seconds to microseconds [12,13,15], with interesting prospects for spectroscopy of short lived transient species. The resolution improves proportionally to the measurement time. Therefore longer recordings allow high resolution spectroscopy of molecules with extreme precision [14,15], since the absolute frequency of each laser comb line can be known with the accuracy of an atomic clock. Selected experimental examples from our group illustrate these features in the next paragraphs. 2 Real-time broad spectral bandwidth absorption spectroscopy An experiment carried out in the telecommunication region may first be used to highlight an important benefit of dual-comb spectroscopy: the extremely short acquisition times [12,13,15]. Two 1550-nm Er-doped fiber lasers emit ~90 fs pulses at a repetition frequency of the order of 100 MHz and 20 mw average output power. The difference between the repetition rates of the two combs is set to a value ranging between 10 Hz and 20 khz. The combs are actively stabilized. The available spectral domain is limited by the Er:doped fiber oscillators to about 120 nm. A single comb interrogates the cell, which is filled with acetylene. The two comb beams are recombined with a beam-mixer. They beat on a fast InGaAs photodiode and the electric signal is amplified and digitized. The upper part of Figure 3 shows an experimental interferogram. Due to the slight mismatch between the constant repetition frequencies of the pulses of the two combs, the interferogram repeats itself at a period, which is the inverse of the difference in the repetition frequencies of the two lasers. Strong bursts occur when pulses from the two lasers overlap. On one side of these bursts, the modulation of the interferogram, zoomed on in the second row of Figure 3, is due to the molecular signatures. When a single comb interrogates the sample, the resulting interferometer can indeed be viewed as the equivalent of a dispersive Fourier transform Michelson interferometer, in which the sample is placed in one arm of the spectrometer. The Fourier transform of a small part of the interferogram time sequence reveals the spectrum (lower part of Fig.3). A spectrum of acetylene in the region of the ν 1 +ν 3 overtone band spans 120 nm and is measured within a single recording of 42 µs, which brings an unapodized resolution of 3 GHz. For comparison, recording such a spectrum with a conventional Fourier transform spectrometer requires more than 10 seconds. The method indeed demonstrates when compared to Michelson-based FT spectroscopy, a million-fold improvement in recording times at identical signal-to-noise ratio. 4
5 Figure 3: The upper part of the figure displays a typical interferogram. It reproduces periodically, with a period equal to 1/Δf r. Depending on the desired optical resolution, the Fourier Transform (FT) of only a portion of this sequence is calculated. For instance, the FT of an interferogram of 42 µs duration is enough to resolve the Doppler-broadened profiles of the molecular sample, as shown on the lower part of the figure. The entire emission domain of the Erbium-fiber lasers is represented. The last row of the figure shows a zoom on the ν 1+ν 3 band of acetylene, at 3 GHz unapodized resolution, resulting from a 42 µs measurement without averaging. Furthermore, due to the periodic structure of the interferogram, one can analyze spectral information at rates above 200 Hz for spectral resolutions at best equal to the comb line spacing. Techniques [17] to increase the refresh rate by changing the difference in repetition frequencies of the two lasers have been proposed, resulting in an intriguing potential for time-resolved spectroscopy of single events. The sensitivity [11] of molecular fingerprinting with dual-comb spectroscopy is dramatically improved when the absorbing sample is placed in a high-finesse optical cavity, because the effective path length is increased. When the equidistant lines from a laser frequency comb are simultaneously injected over a large spectral range into the cavity holding the gas sample, multiple trace gases may be identified within a few tens of microseconds. The cavity finesse determines the enhancement factor for the intracavity absorption signal. Using femtosecond Yb-doped femtosecond fiber lasers that emit around 1.0 µm (Figure 4), weak overtone molecular transitions could be probed with high sensitivity. As an experimental demonstration, the rovibrational spectrum of ammonia, a molecule of astrophysical and environmental interests, is recorded in the region of the 3ν 1 band. The cavity finesse F > 1200 enhances the effective absorption length to 880 m. In Fig. 5, the cavity transmission spans about 20 nm and the spectrum consisting of 1500 spectral elements, with 4.5 GHz resolution and a signal-to-noise ratio of 380, is measured within 18 µs. The weak overtone transitions of the 3ν 1 band are rotationally resolved for the first time, to our knowledge. The minimum-detectable-absorption coefficient α min and the 5
6 noise-equivalent absorption coefficient at 1s-time averaging are cm -1 and cm - 1 Hz -1/2, respectively. This proof-of-principle experiment [11] already demonstrates, with a 100-fold shorter measurement time, a α min coefficient, which is 20-fold better than the one reported in [8]. The spectral bandwidth is presently limited by the Ytterbium amplifier. However, special mirror design managing dispersion has demonstrated [8] to overlap the cavity modes and the comb components across 100 nm simultaneously and the multiplex spectrometer principle allows for the measurement of multi-octave spanning spectra. Therefore a bandwidth of 100 nm should easily achievable by the spectral broadening of the combs with highly nonlinear optical fibers. Figure 4: The interrogating comb pulses are amplified and coupled to a resonant high finesse cavity, which has a free spectral range of 130 MHz and which holds the absorbing sample. The comb is locked to the cavity with a Pound-Drever-Hall scheme. The light leaking out of the cavity beats with the reference comb on a fast photodiode and the electric signal is digitized with a high resolution acquisition board. The Fourier transform of the time domain interference signal reveals the absorption spectrum. Figure 5: Cavity-enhanced dual-comb spectrum of the crowded region of the 3ν 1 overtone band of ammonia. 3 Towards precision dual-comb spectroscopy Frequency combs proved a revolutionary tool for frequency metrology. In dualcomb spectroscopy, increasing the measurement time and including in the Fourier transform calculation a sequence that comprises more than two bursts (upper part of Figure 3) enables to resolve the individual comb lines. The resulting spectra [13] are sampled by 6
7 Figure 6 : Dual-comb spectrum spanning 105 nm with 420 khz apodised optical resolution. The Fourier transform of an interferogram made of 536 millions samples recorded in 3.35 s is successively zoomed to display very well resolved comb lines and a single experimental comb line profile drawn on such a frequency scale that the entire spectrum would need a 90 km-wide page. Figure 7: Spectrum of resolved comb lines with KHz width in the optical domain in a 536 Megasamples dualcomb spectrum measured within 6 s. a, 1-nm wide spectrum revealing several acetylene profiles shaping the discrete comb line intensities. b, Zoom on the P e(27) line of the ν 1+ν 3 band. c, Zoom on one single comb line illustrating the 2,300 Hz apodised optical resolution. combs of 100-MHz line-spacing that may cover domains of tens of nm (Figure 6) with comb lines exhibiting khz optical linewidth (Figure 7). A dense grid of accurate frequency markers therefore allows for precise self-calibration of the frequency scale. However the molecular spectra are sampled by the comb line spacing, with a step equal to the repetition frequency. As the comb repetition frequency most often lies between 50 MHz and 200 MHz, most of molecular profiles at room temperature in the gas phase are appropriately sampled by the line spacing of the comb. In case better resolutions would be needed, interleaving techniques [13,15] may sample the spectra down to the ultimate optical 7
8 resolution imposed by the width of the comb lines. 4 Adaptive dual-comb spectroscopy The recording of distorsion-free spectra requires demanding servo-control [13-15] of the laser combs or computer-based a posteriori corrections [20]: typically the timing jitter from the subsequent interfering pulses has to be of the order of 1 to 10 attoseconds. When this is not achieved, chromatic distortions, called phase errors, cannot be accounted for a posteriori and produce artifacts, which may totally scramble the spectral information. Most of the potential applications of dual-comb spectroscopy require the recording of broadband spectra without sharp features, as they are e.g. encountered in the gas phase with Doppler-broadened transitions or in the liquid phase. Simple instrumental schemes that would keep the very fast recording times of dual-comb spectroscopy are therefore desirable. An adaptive sampling technique that allows recording such distorsion-free spectra with free-running femtosecond lasers has been developed and it has been demonstrated with commercial fiber lasers emitting around 1.0 µm. Adaptive sampling [22] allows for fluctuations in the repetition frequency and pulse-to-pulse phase shift of the femtosecond lasers and produces a clock signal synchronous to these fluctuations that triggers the sampling of the interference pattern generated by the two combs. This adaptive sampling uses the reference signal of the beat between one pair of lines of the two combs. This reference signal is then electronically multiplied to meet the Nyquist criterion, producing a clock for data acquisition, which compensates for the optical delay fluctuations of the interferogram, so that sampling occurs at even optical delays, leading to distortion-less spectra. In an implementation of the adaptive sampling scheme, free-running commercial Ytterbium femtosecond lasers are used with a repetition frequency of 100 MHz and a difference in repetition frequency of about 121 Hz. The lasers are placed in a basic laboratory environment, without air-conditioning system, vibration isolation or dust protection. Each laser beats with a continuous-wave 1040 nm ytterbium fiber laser. Mixing the beating signal generates a 20 MHz reference that is frequency-multiplied four-fold to produce a 80 MHz clock signal which is connected to the external clock input of the data acquisition board. The two femtosecond lasers beams are also combined on a beam mixer and interrogate a Fabry-Pérot resonator with a free spectral range of 49.1 GHz and a finesse of The time-domain interference pattern of the Fabry-Pérot transmission is sampled by the data acquisition board at the clock frequency. An interferogram with samples measured within 1.6 ms is Fourier transformed to uncover a spectrum with 489 MHz resolution displayed in Figure 8. Figure 8a shows the full spectral span. Figure 8b compares a small portion of the spectrum resulting of an interferogram with adaptive sampling and that of an interferogram sampled with internal clock of the data. Without the adaptive sampling, not only the transmission function of the resonator is spectrally strongly scrambled but also successive acquisitions dramatically differ so that averaging spectra is impossible. 8
9 a) b) Figure 8: a. Fabry-Pérot transmission spectra taken with the adaptive sampling technique over the full emission range of Yb fs lasers. The red line marked cw indicates the frequency of the continuous-wave laser used to isolate the beating signal between one line of each comb. The correction for the relative comb fluctuations is better in the vicinity of this frequency. b. Comparison between spectra measured with free running lasers and a) the adaptive clock, b) the internal clock of the data acquisition board. Five sequential spectra (N=1-5) and their average are shown. 4 Conclusion The spectral structure of sharp lines of a laser comb proves very useful even in the recording of broadband spectra without sharp features, as they are e.g. encountered for molecular gases or in the liquid phase. Dual-comb spectroscopy demonstrates a millionfold improvement in the recording time, the resolution and the sensitivity of broad spectral bandwidth linear absorption spectroscopy. A similar improvement in the accuracy may come into reach with Doppler-free spectra. Laser combs in combination with other advancing tools of laser science, nonlinear optics, photonics, and electronic signal processing may vastly enhance the range and capabilities of molecular laser spectroscopy. Molecular physics with laser frequency combs is however still in its infancy. Several challenging issues, like the development of suitable comb sources in the molecular fingerprint mid-infrared and ultraviolet regions, still need to be overcome before the full potential of such techniques can be realized. The interdisciplinary scientific outcomes of comb-based spectroscopic tools will mostly depend on the instrumental characteristics that will be achieved, but frequency comb spectroscopy might establish the basis of groundbreaking spectroscopic tools and open up new insights in the understanding of the structure of matter as well as new horizons in advanced diagnostics instruments, for instance in chemistry or biomedicine. Acknowledgements Research conducted in the scope of the European Associated Laboratory European Laboratory for Frequency Comb Spectroscopy. Support by the Max Planck Foundation, the Munich Center for Advanced Photonics, the Triangle de la Physique, the E.A.D.S Foundation, the Conseil Général de l Essonne and the Agence Nationale de la Recherche is gratefully acknowledged. Guy Guelachvili, Birgitta Bernhardt, Patrick Jacquet, Takuro Ideguchi, Julien Mandon and Antonin Poisson are warmly acknowledged for their contribution to the work reported here. 9
10 References [1] T.W. Hänsch, Nobel Lecture: Passion for precision, Rev. Mod. Phys. 78, (2006). [2] T. Udem, R. Holzwarth, T.W. Ηänsch, Optical frequency metrology, Nature 416, (2002). [3] J. Mandon, G. Guelachvili, and N. Picqué, Fourier transform spectroscopy with a laser frequency comb. Nature Photonics 3, (2009). [4] J. Mandon, G. Guelachvili, N. Picqué, F. Druon, P. Georges, Femtosecond laser Fourier transform absorption spectroscopy, Optics Letters 32, (2007) [5] E. Sorokin, I.T. Sorokina, J. Mandon, G. Guelachvili, N. Picqué, Sensitive multiplex spectroscopy in the molecular fingerprint 2.4 µm region with a Cr 2+ :ZnSe femtosecond laser, Optics Express 15, (2007). [6] F. Adler, P. Masłowski, A. Foltynowicz, K.C. Cossel, T.C. Briles, I. Hartl, and J. Ye, Midinfrared Fourier transform spectroscopy with a broadband frequency comb, Optics Express 18, (2010) [7] S.A. Diddams, L. Hollberg, and V. Mbele, Molecular fingerprinting with the resolved modes of a femtosecond laser frequency comb. Nature 445, (2007). [8] M.J. Thorpe, et al., Broadband cavity ringdown spectroscopy for sensitive and rapid molecular detection. Science 311, (2006). [9] F. Adler, et al., Cavity-Enhanced Direct Frequency Comb Spectroscopy: Technology and Applications. Annual Review of Analytical Chemistry 3, (2010). [10] C. Gohle, B. Stein, A. Schliesser, T. Udem, T.W. Hänsch, Frequency comb Vernier spectroscopy for broadband, high-resolution, high-sensitivity absorption and dispersion spectra. Phys. Rev. Lett. 99, (2007). [11] B. Bernhardt, et al., Cavity-enhanced dual-comb spectroscopy. Nature Photonics 4, (2010). [12] B. Bernhardt, et al., Mid-infrared dual-comb spectroscopy with 2.4 µm Cr(2+):ZnSe femtosecond lasers. Applied Physics B-Lasers and Optics 100, 3-8 (2010). [13] J. Mandon, Spectroscopie de Fourier par peignes de fréquences femtosecondes, Thèse de doctorat en sciences de l Université Paris-Sud, (2009). [14] I. Coddington, W.C. Swann, N.R. Newbury, Coherent multiheterodyne spectroscopy using stabilized optical frequency combs. Phys. Rev. Lett. 100, (2008). [15] P. Jacquet, et al. Frequency Comb Fourier Transform Spectroscopy with khz Optical Resolution. in Fourier Transform Spectroscopy (Optical Society of America, Washington, DC, 2009), paper FMB2, 3 pages (2009). [16] F. Keilmann, C. Gohle, R. Holzwarth, Time-domain mid-infrared frequency-comb spectrometer. Opt. Lett. 29, (2004). [17] A. Schliesser, M. Brehm, F. Keilmann, D.W. van der Weide, Frequency-comb infrared spectrometer for rapid, remote chemical sensing. Opt. Express 13, (2005). [18] T. Yasui, E. Saneyoshi, T. Araki, Asynchronous optical sampling terahertz time-domain spectroscopy for ultrahigh spectral resolution and rapid data acquisition, Appl. Phys. Lett. 87, (2005). [19] I. Coddington, W. C. Swann, and N. R. Newbury, Coherent dual-comb spectroscopy at high signal-to-noise ratio, Phys. Rev. A 82, (2010). [20] P. Giaccari, et al. Active Fourier-transform spectroscopy combining the direct RF beating of two fiber-based mode-locked lasers with a novel referencing method. Opt. Express 16, (2008). [21] T. Ideguchi, A. Poisson, G. Guelachvili, T.W. Hänsch, and N. Picqué, "Dual-comb spectroscopy with adaptive sampling," in CLEO/Europe and EQEC 2011 Conference Digest, OSA Technical Digest (CD) (Optical Society of America, 2011), paper CH_P23. [22] G. Berden, R. Engeln, Eds. Cavity Ring Down Spectroscopy: Techniques and Applications, Wiley, September 2009, ISBN:
Introduction to Fourier Transform Infrared Spectrometry
Introduction to Fourier Transform Infrared Spectrometry What is FT-IR? I N T R O D U C T I O N FT-IR stands for Fourier Transform InfraRed, the preferred method of infrared spectroscopy. In infrared spectroscopy,
More informationA bidirectional dual-comb ring laser for simple and robust dualcomb spectroscopy
A bidirectional dual-comb ring laser for simple and robust dualcomb spectroscopy Takuro Ideguchi 1,*, Tasuku Nakamura 2, Yohei Kobayashi 3 & Keisuke Goda 2,4,5,* 1 Research Centre for Spectrochemistry,
More informationFTIR Instrumentation
FTIR Instrumentation Adopted from the FTIR lab instruction by H.-N. Hsieh, New Jersey Institute of Technology: http://www-ec.njit.edu/~hsieh/ene669/ftir.html 1. IR Instrumentation Two types of instrumentation
More informationExperiment 5. Lasers and laser mode structure
Northeastern University, PHYS5318 Spring 2014, 1 1. Introduction Experiment 5. Lasers and laser mode structure The laser is a very important optical tool that has found widespread use in science and industry,
More informationPUMPED Nd:YAG LASER. Last Revision: August 21, 2007
PUMPED Nd:YAG LASER Last Revision: August 21, 2007 QUESTION TO BE INVESTIGATED: How can an efficient atomic transition laser be constructed and characterized? INTRODUCTION: This lab exercise will allow
More informationModule 13 : Measurements on Fiber Optic Systems
Module 13 : Measurements on Fiber Optic Systems Lecture : Measurements on Fiber Optic Systems Objectives In this lecture you will learn the following Measurements on Fiber Optic Systems Attenuation (Loss)
More informationFundamentals of modern UV-visible spectroscopy. Presentation Materials
Fundamentals of modern UV-visible spectroscopy Presentation Materials The Electromagnetic Spectrum E = hν ν = c / λ 1 Electronic Transitions in Formaldehyde 2 Electronic Transitions and Spectra of Atoms
More informationThe Fundamentals of Infrared Spectroscopy. Joe Van Gompel, PhD
TN-100 The Fundamentals of Infrared Spectroscopy The Principles of Infrared Spectroscopy Joe Van Gompel, PhD Spectroscopy is the study of the interaction of electromagnetic radiation with matter. The electromagnetic
More informationFour Wave Mixing in Closely Spaced DWDM Optical Channels
544 VOL. 1, NO. 2, AUGUST 2006 Four Wave Mixing in Closely Spaced DWDM Optical Channels Moncef Tayahi *, Sivakumar Lanka, and Banmali Rawat Advanced Photonics Research lab, Department of Electrical Engineering
More informationScalable Frequency Generation from Single Optical Wave
Scalable Frequency Generation from Single Optical Wave S. Radic Jacobs School Of Engineering Qualcomm Institute University of California San Diego - Motivation - Bandwidth Engineering - Noise Inhibition
More informationANALYZER BASICS WHAT IS AN FFT SPECTRUM ANALYZER? 2-1
WHAT IS AN FFT SPECTRUM ANALYZER? ANALYZER BASICS The SR760 FFT Spectrum Analyzer takes a time varying input signal, like you would see on an oscilloscope trace, and computes its frequency spectrum. Fourier's
More informationExperiment #5: Qualitative Absorption Spectroscopy
Experiment #5: Qualitative Absorption Spectroscopy One of the most important areas in the field of analytical chemistry is that of spectroscopy. In general terms, spectroscopy deals with the interactions
More informationData Transmission. Data Communications Model. CSE 3461 / 5461: Computer Networking & Internet Technologies. Presentation B
CSE 3461 / 5461: Computer Networking & Internet Technologies Data Transmission Presentation B Kannan Srinivasan 08/30/2012 Data Communications Model Figure 1.2 Studying Assignment: 3.1-3.4, 4.1 Presentation
More informationE. K. A. ADVANCED PHYSICS LABORATORY PHYSICS 3081, 4051 NUCLEAR MAGNETIC RESONANCE
E. K. A. ADVANCED PHYSICS LABORATORY PHYSICS 3081, 4051 NUCLEAR MAGNETIC RESONANCE References for Nuclear Magnetic Resonance 1. Slichter, Principles of Magnetic Resonance, Harper and Row, 1963. chapter
More information13C NMR Spectroscopy
13 C NMR Spectroscopy Introduction Nuclear magnetic resonance spectroscopy (NMR) is the most powerful tool available for structural determination. A nucleus with an odd number of protons, an odd number
More informationSpectroscopy. Biogeochemical Methods OCN 633. Rebecca Briggs
Spectroscopy Biogeochemical Methods OCN 633 Rebecca Briggs Definitions of Spectrometry Defined by the method used to prepare the sample 1. Optical spectrometry Elements are converted to gaseous atoms or
More information- thus, the total number of atoms per second that absorb a photon is
Stimulated Emission of Radiation - stimulated emission is referring to the emission of radiation (a photon) from one quantum system at its transition frequency induced by the presence of other photons
More informationProblem Set 6 UV-Vis Absorption Spectroscopy. 13-1. Express the following absorbances in terms of percent transmittance:
Problem Set 6 UV-Vis Absorption Spectroscopy 13-1. Express the following absorbances in terms of percent transmittance: a 0.051 b 0.918 c 0.379 d 0.261 e 0.485 f 0.072 A = log P o /P = log1/t = - log T
More informationRealtime FFT processing in Rohde & Schwarz receivers
Realtime FFT in Rohde & Schwarz receivers Radiomonitoring & Radiolocation Application Brochure 01.00 Realtime FFT in Rohde & Schwarz receivers Introduction This application brochure describes the sophisticated
More informationFibre Bragg Grating Sensors An Introduction to Bragg gratings and interrogation techniques
Fibre Bragg Grating Sensors An ntroduction to Bragg gratings and interrogation techniques Dr Crispin Doyle Senior Applications Engineer, Smart Fibres Ltd. 2003 1) The Fibre Bragg Grating (FBG) There are
More informationSpectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry
Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Jon H. Hardesty, PhD and Bassam Attili, PhD Collin College Department of Chemistry Introduction: In the last lab
More informationMeasuring Laser Power and Energy Output
Measuring Laser Power and Energy Output Introduction The most fundamental method of checking the performance of a laser is to measure its power or energy output. Laser output directly affects a laser s
More informationFrank C. De Lucia Ivan R. Medvedev Christopher F. Neese Grant M. Plummer. Ohio State University Enthalpy Analytical
The impact of CMOS technology on mass market applications in the submillimeter/terahertz spectral region: chemical sensors and imaging through obstruction Frank C. De Lucia Ivan R. Medvedev Christopher
More informationDoppler. Doppler. Doppler shift. Doppler Frequency. Doppler shift. Doppler shift. Chapter 19
Doppler Doppler Chapter 19 A moving train with a trumpet player holding the same tone for a very long time travels from your left to your right. The tone changes relative the motion of you (receiver) and
More informationJeff Thomas Tom Holmes Terri Hightower. Learn RF Spectrum Analysis Basics
Jeff Thomas Tom Holmes Terri Hightower Learn RF Spectrum Analysis Basics Learning Objectives Name the major measurement strengths of a swept-tuned spectrum analyzer Explain the importance of frequency
More informationR&S FSW signal and spectrum analyzer: best in class now up to 50 GHz
R&S FSW signal and spectrum analyzer: best in class now up to 50 GHz The new R&S FSW 43 and R&S FSW 50 signal and spectrum analyzers make the outstanding features of the R&S FSW family available now also
More informationDesigning and Manufacturing Femtoseconds Ultra-broadband Lasers: Proven, Hands-free Reliability
Technical Note Designing and Manufacturing Femtoseconds Ultra-broadband Lasers: Proven, Hands-free Reliability This whitepaper reviews how design choices, manufacturing steps and testing protocols substantially
More informationIndustrial Process Monitoring Requires Rugged AOTF Tools
Industrial Process Monitoring Requires Rugged AOTF Tools Dr Jolanta Soos Growth has been rapid in the use of spectroscopic methods to monitor industrial processes, both in production lines and for quality
More informationQuantum cascade laser based TERAhertz frequency COMB
Quantum cascade laser based TERAhertz frequency COMB (FET open project and a way into it...) www.teracomb.eu Juraj Darmo Technische Universität Wien, Ins1tut für Fotonik Talk outline 1. TERACOMB facts
More informationInfrared Spectroscopy 紅 外 線 光 譜 儀
Infrared Spectroscopy 紅 外 線 光 譜 儀 Introduction Spectroscopy is an analytical technique which helps determine structure. It destroys little or no sample (nondestructive method). The amount of light absorbed
More informationFrom lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation?
From lowest energy to highest energy, which of the following correctly orders the different categories of electromagnetic radiation? From lowest energy to highest energy, which of the following correctly
More informationRaman Spectroscopy Basics
Raman Spectroscopy Basics Introduction Raman spectroscopy is a spectroscopic technique based on inelastic scattering of monochromatic light, usually from a laser source. Inelastic scattering means that
More informationSynthetic Sensing: Proximity / Distance Sensors
Synthetic Sensing: Proximity / Distance Sensors MediaRobotics Lab, February 2010 Proximity detection is dependent on the object of interest. One size does not fit all For non-contact distance measurement,
More informationComponents for Infrared Spectroscopy. Dispersive IR Spectroscopy
Components for Infrared Spectroscopy Mid-IR light: 00-000 cm - (5.5 m wavelength) Sources: Blackbody emitters Globar metal oxides Nernst Glower: Silicon Carbide Detectors: Not enough energy for photoelectric
More informationInstallation, Commissioning and Operation of the Master Laser Oscillator at FLASH
Installation, Commissioning and Operation of the Master Laser Oscillator at FLASH Patrick Geßler DESY II Timing & Synchronization Workshop, ICTP, Trieste 09.03.2009 V. Arsov, B. Bayer, M. K. Bock, M. Felber,
More informationStatus of the FERMI@Elettra Free Electron Laser
Status of the FERMI@Elettra Free Electron Laser E. Allaria on behalf of the FERMI team Work partially supported by the Italian Ministry of University and Research under grants FIRB-RBAP045JF2 and FIRB-RBAP06AWK3
More informationHD Radio FM Transmission System Specifications Rev. F August 24, 2011
HD Radio FM Transmission System Specifications Rev. F August 24, 2011 SY_SSS_1026s TRADEMARKS HD Radio and the HD, HD Radio, and Arc logos are proprietary trademarks of ibiquity Digital Corporation. ibiquity,
More informationScanning Near Field Optical Microscopy: Principle, Instrumentation and Applications
Scanning Near Field Optical Microscopy: Principle, Instrumentation and Applications Saulius Marcinkevičius Optics, ICT, KTH 1 Outline Optical near field. Principle of scanning near field optical microscope
More informationA More Efficient Way to De-shelve 137 Ba +
A More Efficient Way to De-shelve 137 Ba + Abstract: Andrea Katz Trinity University UW REU 2010 In order to increase the efficiency and reliability of de-shelving barium ions, an infrared laser beam was
More informationPump-probe experiments with ultra-short temporal resolution
Pump-probe experiments with ultra-short temporal resolution PhD candidate: Ferrante Carino Advisor:Tullio Scopigno Università di Roma ƒla Sapienza 22 February 2012 1 Pump-probe experiments: generalities
More informationRaman spectroscopy Lecture
Raman spectroscopy Lecture Licentiate course in measurement science and technology Spring 2008 10.04.2008 Antti Kivioja Contents - Introduction - What is Raman spectroscopy? - The theory of Raman spectroscopy
More informationULTRAFAST LASERS: Free electron lasers thrive from synergy with ultrafast laser systems
Page 1 of 6 ULTRAFAST LASERS: Free electron lasers thrive from synergy with ultrafast laser systems Free electron lasers support unique time-resolved experiments over a wide range of x-ray wavelengths,
More informationPIPELINE LEAKAGE DETECTION USING FIBER-OPTIC DISTRIBUTED STRAIN AND TEMPERATURE SENSORS WHITE PAPER
PIPELINE LEAKAGE DETECTION USING FIBER-OPTIC DISTRIBUTED STRAIN AND TEMPERATURE SENSORS WHITE PAPER Lufan Zou and Taha Landolsi OZ Optics Limited, 219 Westbrook Road, Ottawa, ON, Canada, K0A 1L0 E-mail:
More informationINFRARED SPECTROSCOPY (IR)
INFRARED SPECTROSCOPY (IR) Theory and Interpretation of IR spectra ASSIGNED READINGS Introduction to technique 25 (p. 833-834 in lab textbook) Uses of the Infrared Spectrum (p. 847-853) Look over pages
More informationSignal to Noise Instrumental Excel Assignment
Signal to Noise Instrumental Excel Assignment Instrumental methods, as all techniques involved in physical measurements, are limited by both the precision and accuracy. The precision and accuracy of a
More informationAn optical readout configuration for advanced massive GW detectors
An optical readout configuration for advanced massive GW detectors Francesco Marin, Livia Conti, Maurizio De Rosa Dipartimento di Fisica, Università di Firenze,LENS and INFN, Sezione di Firenze Via Sansone,
More informationApplication Note AN-00126
Considerations for Operation within the 902-928MHz Band Application Note AN-00126 Introduction This application note is designed to give the reader a basic understanding of the legal and technical considerations
More informationTi:Sapphire Lasers. Tyler Bowman. April 23, 2015
Ti:Sapphire Lasers Tyler Bowman April 23, 2015 Introduction Ti:Sapphire lasers are a solid state laser group based on using titanium-doped sapphire (Ti:Al 2O 3) plates as a gain medium. These lasers are
More informationRF Measurements Using a Modular Digitizer
RF Measurements Using a Modular Digitizer Modern modular digitizers, like the Spectrum M4i series PCIe digitizers, offer greater bandwidth and higher resolution at any given bandwidth than ever before.
More informationMATRIX TECHNICAL NOTES
200 WOOD AVENUE, MIDDLESEX, NJ 08846 PHONE (732) 469-9510 FAX (732) 469-0418 MATRIX TECHNICAL NOTES MTN-107 TEST SETUP FOR THE MEASUREMENT OF X-MOD, CTB, AND CSO USING A MEAN SQUARE CIRCUIT AS A DETECTOR
More informationOptical Fibres. Introduction. Safety precautions. For your safety. For the safety of the apparatus
Please do not remove this manual from from the lab. It is available at www.cm.ph.bham.ac.uk/y2lab Optics Introduction Optical fibres are widely used for transmitting data at high speeds. In this experiment,
More informationElectronic Communications Committee (ECC) within the European Conference of Postal and Telecommunications Administrations (CEPT)
Page 1 Electronic Communications Committee (ECC) within the European Conference of Postal and Telecommunications Administrations (CEPT) ECC RECOMMENDATION (06)01 Bandwidth measurements using FFT techniques
More informationApplication Note AN1
TAKING INVENTIVE STEPS IN INFRARED. MINIATURE INFRARED GAS SENSORS GOLD SERIES UK Patent App. No. 799A USA Patent App. No. 9/78,7 World Patents Pending SENSOR OVERVIEW Application Note AN The Dynament
More informationThe photoionization detector (PID) utilizes ultraviolet
Chapter 6 Photoionization Detectors The photoionization detector (PID) utilizes ultraviolet light to ionize gas molecules, and is commonly employed in the detection of volatile organic compounds (VOCs).
More informationIt has long been a goal to achieve higher spatial resolution in optical imaging and
Nano-optical Imaging using Scattering Scanning Near-field Optical Microscopy Fehmi Yasin, Advisor: Dr. Markus Raschke, Post-doc: Dr. Gregory Andreev, Graduate Student: Benjamin Pollard Department of Physics,
More informationAN1200.04. Application Note: FCC Regulations for ISM Band Devices: 902-928 MHz. FCC Regulations for ISM Band Devices: 902-928 MHz
AN1200.04 Application Note: FCC Regulations for ISM Band Devices: Copyright Semtech 2006 1 of 15 www.semtech.com 1 Table of Contents 1 Table of Contents...2 1.1 Index of Figures...2 1.2 Index of Tables...2
More informationA PC-BASED TIME INTERVAL COUNTER WITH 200 PS RESOLUTION
35'th Annual Precise Time and Time Interval (PTTI) Systems and Applications Meeting San Diego, December 2-4, 2003 A PC-BASED TIME INTERVAL COUNTER WITH 200 PS RESOLUTION Józef Kalisz and Ryszard Szplet
More informationTime out states and transitions
Time out states and transitions Spectroscopy transitions between energy states of a molecule excited by absorption or emission of a photon hn = DE = E i - E f Energy levels due to interactions between
More informationImproving Chromatic Dispersion and PMD Measurement Accuracy
Improving Chromatic Dispersion and PMD Measurement Accuracy White Paper Michael Kelly Agilent Technologies Signal transmission over optical fibers relies on preserving the waveform from transmitter to
More informationHP 70950B OPTICAL SPECTRUM ANALYZER
HP 71450B, 71451B, and 71452B Optical Spectrum Analyzers Technical Specifications Spectral Measurements from 600 to 1700 nm HP 70950B OPTICAL SPECTRUM ANALYZER OPTICAL INPUT The HP 71450B, 71451B, and
More informationTCOM 370 NOTES 99-4 BANDWIDTH, FREQUENCY RESPONSE, AND CAPACITY OF COMMUNICATION LINKS
TCOM 370 NOTES 99-4 BANDWIDTH, FREQUENCY RESPONSE, AND CAPACITY OF COMMUNICATION LINKS 1. Bandwidth: The bandwidth of a communication link, or in general any system, was loosely defined as the width of
More informationChallenges in DWDM System Spectral Analysis By Laurent Begin and Jim Nerschook
Challenges in DWDM System Spectral Analysis By Laurent Begin and Jim Nerschook TABLE OF CONTENTS: 1.0 Satisfying the Thirst for Bandwidth 02 2.0 The Solution, DWDM 02 3.0 Resolution 04 4.0 Wavelength Accuracy
More informationAgilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy
Agilent AN 1316 Optimizing Spectrum Analyzer Amplitude Accuracy Application Note RF & Microwave Spectrum Analyzers Table of Contents 3 3 4 4 5 7 8 8 13 13 14 16 16 Introduction Absolute versus relative
More informationChapter 6 Bandwidth Utilization: Multiplexing and Spreading 6.1
Chapter 6 Bandwidth Utilization: Multiplexing and Spreading 6.1 Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Note Bandwidth utilization is the wise use of
More informationPCM Encoding and Decoding:
PCM Encoding and Decoding: Aim: Introduction to PCM encoding and decoding. Introduction: PCM Encoding: The input to the PCM ENCODER module is an analog message. This must be constrained to a defined bandwidth
More informationEmail: tjohn@mail.nplindia.ernet.in
USE OF VIRTUAL INSTRUMENTS IN RADIO AND ATMOSPHERIC EXPERIMENTS P.N. VIJAYAKUMAR, THOMAS JOHN AND S.C. GARG RADIO AND ATMOSPHERIC SCIENCE DIVISION, NATIONAL PHYSICAL LABORATORY, NEW DELHI 110012, INDIA
More informationInterferometric Measurement of Dispersion in Optical Components
Interferometric Measurement of Dispersion in Optical Components Mark Froggatt, Eric Moore, and Matthew Wolfe Luna Technologies, Incorporated, 293-A Commerce Street, Blacksburg, Virginia 246 froggattm@lunatechnologies.com.
More informationShort overview of TEUFEL-project
Short overview of TEUFEL-project ELAN-meeting may 2004 Frascati (I) Contents Overview of TEUFEL project at Twente Photo cathode research Recent experience Outlook Overview FEL Drive laser Photo cathode
More informationQuantum cascade lasers for TDLS
Quantum cascade lasers for TDLS Stéphane Blaser 1-3 Maximilien-de-Meuron CH-2000 Neuchâtel Switzerland 5th International Conference on Tunable Diode Laser Spectroscopy (TDLS) Industry Session, July 12,
More informationT = 1 f. Phase. Measure of relative position in time within a single period of a signal For a periodic signal f(t), phase is fractional part t p
Data Transmission Concepts and terminology Transmission terminology Transmission from transmitter to receiver goes over some transmission medium using electromagnetic waves Guided media. Waves are guided
More informationTetramethylsilane (TMS) Trimethylsilyl d 4. -propionic acid (TMSP) Dioxane. O - Na + Dimethylfura n. Potassium Hydrogen Phthalate. Sodium Maleate CH 3
Practical Aspects of Quantitative NMR Experiments This discussion presumes that you already have an understanding of the basic theory of NMR. There are a number of issues that should be considered when
More informationRadiant Dyes Laser Accessories GmbH
New NarrowScan New Resonator Design Improved Sine Drive Unit Autotracking Frequency doubling, tripling and mixing Wavelength Separation Unit Frequency Stabilization Temperature Stabilization Wavelength
More informationMolecular Spectroscopy
Molecular Spectroscopy UV-Vis Spectroscopy Absorption Characteristics of Some Common Chromophores UV-Vis Spectroscopy Absorption Characteristics of Aromatic Compounds UV-Vis Spectroscopy Effect of extended
More informationFIBER LASER STRAIN SENSOR DEVICE
FIBER LASER STRAIN SENSOR DEVICE E. Maccioni (1,2), N. Beverini (1,2), M. Morganti (1,2) F. Stefani (2,3), R. Falciai (4), C. Trono (4) (1) Dipartimento di Fisica E. Fermi Pisa (2) INFN Sez. Pisa (3) Dipartimento
More informationNano-Spectroscopy. Solutions AFM-Raman, TERS, NSOM Chemical imaging at the nanoscale
Nano-Spectroscopy Solutions AFM-Raman, TERS, NSOM Chemical imaging at the nanoscale Since its introduction in the early 80 s, Scanning Probe Microscopy (SPM) has quickly made nanoscale imaging an affordable
More informationThe EMI-Receiver according to CISPR 16-1-1
Author: Dipl. -Ing. Dieter Schwarzbeck Schwarzbeck Mess-Elektronik An der Klinge 29 D-69250 Schönau / Germany Tel.: +49 6228 1001 Fax.:+49 6228 1003 support@schwarzbeck.de www.schwarzbeck.de Requirements
More informationRealization of a UV fisheye hyperspectral camera
Realization of a UV fisheye hyperspectral camera Valentina Caricato, Andrea Egidi, Marco Pisani and Massimo Zucco, INRIM Outline Purpose of the instrument Required specs Hyperspectral technique Optical
More informationMaking OSNR Measurements In a Modulated DWDM Signal Environment
Making OSNR Measurements In a Modulated DWDM Signal Environment Jack Dupre Jim Stimple Making OSNR measurements in a modulated DWDM signal environment May 2001 In a DWDM spectrum, it is desirable to measure
More informationTechnical Datasheet Scalar Network Analyzer Model 8003-10 MHz to 40 GHz
Technical Datasheet Scalar Network Analyzer Model 8003-10 MHz to 40 GHz The Giga-tronics Model 8003 Precision Scalar Network Analyzer combines a 90 db wide dynamic range with the accuracy and linearity
More informationApplication Note: Spread Spectrum Oscillators Reduce EMI for High Speed Digital Systems
Application Note: Spread Spectrum Oscillators Reduce EMI for High Speed Digital Systems Introduction to Electro-magnetic Interference Design engineers seek to minimize harmful interference between components,
More informationDispersion in Optical Fibers
Dispersion in Optical Fibers By Gildas Chauvel Anritsu Corporation TABLE OF CONTENTS Introduction Chromatic Dispersion (CD): Definition and Origin; Limit and Compensation; and Measurement Methods Polarization
More informationExtended Resolution TOA Measurement in an IFM Receiver
Extended Resolution TOA Measurement in an IFM Receiver Time of arrival (TOA) measurements define precisely when an RF signal is received, necessary in the identification of type and mode of RF and radar
More informationDevelopment of Optical Wave Microphone Measuring Sound Waves with No Diaphragm
Progress In Electromagnetics Research Symposium Proceedings, Taipei, March 5 8, 3 359 Development of Optical Wave Microphone Measuring Sound Waves with No Diaphragm Yoshito Sonoda, Takashi Samatsu, and
More informationAnalysis and Improvement of Mach Zehnder Modulator Linearity Performance for Chirped and Tunable Optical Carriers
886 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 20, NO. 5, MAY 2002 Analysis and Improvement of Mach Zehnder Modulator Linearity Performance for Chirped and Tunable Optical Carriers S. Dubovitsky, Member, IEEE,
More informationSpectral Measurement Solutions for Industry and Research
Spectral Measurement Solutions for Industry and Research Hamamatsu Photonics offers a comprehensive range of products for spectroscopic applications, covering the, Visible and Infrared regions for Industrial,
More informationDesign and Test of Fast Laser Driver Circuits
Design and Test of Fast Laser Driver Circuits Since the invention of the laser by Theodore H Maiman 50 years ago, lasers have found widespread applications in various technological fields, such as telecommunications,
More informationRECOMMENDATION ITU-R SM.1792. Measuring sideband emissions of T-DAB and DVB-T transmitters for monitoring purposes
Rec. ITU-R SM.1792 1 RECOMMENDATION ITU-R SM.1792 Measuring sideband emissions of T-DAB and DVB-T transmitters for monitoring purposes (2007) Scope This Recommendation provides guidance to measurement
More informationModern Classical Optics
Modern Classical Optics GEOFFREY BROOKER Department of Physics University of Oxford OXPORD UNIVERSITY PRESS Contents 1 Electromagnetism and basic optics 1 1.1 Introduction 1 1.2 The Maxwell equations 1
More informationHigh-Concentration Submicron Particle Size Distribution by Dynamic Light Scattering
High-Concentration Submicron Particle Size Distribution by Dynamic Light Scattering Power spectrum development with heterodyne technology advances biotechnology and nanotechnology measurements. M. N. Trainer
More informationUses of Derivative Spectroscopy
Uses of Derivative Spectroscopy Application Note UV-Visible Spectroscopy Anthony J. Owen Derivative spectroscopy uses first or higher derivatives of absorbance with respect to wavelength for qualitative
More informationFluorescent dyes for use with the
Detection of Multiple Reporter Dyes in Real-time, On-line PCR Analysis with the LightCycler System Gregor Sagner, Cornelia Goldstein, and Rob van Miltenburg Roche Molecular Biochemicals, Penzberg, Germany
More informationAbsorption by atmospheric gases in the IR, visible and UV spectral regions.
Lecture 6. Absorption by atmospheric gases in the IR, visible and UV spectral regions. Objectives: 1. Gaseous absorption in thermal IR. 2. Gaseous absorption in the visible and near infrared. 3. Gaseous
More informationINTRODUCTION FIGURE 1 1. Cosmic Rays. Gamma Rays. X-Rays. Ultraviolet Violet Blue Green Yellow Orange Red Infrared. Ultraviolet.
INTRODUCTION Fibre optics behave quite different to metal cables. The concept of information transmission is the same though. We need to take a "carrier" signal, identify a signal parameter we can modulate,
More informationAcousto-optic modulator
1 of 3 Acousto-optic modulator F An acousto-optic modulator (AOM), also called a Bragg cell, uses the acousto-optic effect to diffract and shift the frequency of light using sound waves (usually at radio-frequency).
More informationReal-world applications of intense light matter interaction beyond the scope of classical micromachining.
Dr. Lukas Krainer lk@onefive.com CEO Real-world applications of intense light matter interaction beyond the scope of classical micromachining. 1 Management & Company Company Based in Zürich, Switzerland
More informationOptical Communications
Optical Communications Telecommunication Engineering School of Engineering University of Rome La Sapienza Rome, Italy 2005-2006 Lecture #2, May 2 2006 The Optical Communication System BLOCK DIAGRAM OF
More informationInfrared Spectroscopy: Theory
u Chapter 15 Infrared Spectroscopy: Theory An important tool of the organic chemist is Infrared Spectroscopy, or IR. IR spectra are acquired on a special instrument, called an IR spectrometer. IR is used
More informationTechnical Note. Roche Applied Science. No. LC 19/2004. Color Compensation
Roche Applied Science Technical Note No. LC 19/2004 Purpose of this Note Color The LightCycler System is able to simultaneously detect and analyze more than one color in each capillary. Due to overlap
More informationNon-Data Aided Carrier Offset Compensation for SDR Implementation
Non-Data Aided Carrier Offset Compensation for SDR Implementation Anders Riis Jensen 1, Niels Terp Kjeldgaard Jørgensen 1 Kim Laugesen 1, Yannick Le Moullec 1,2 1 Department of Electronic Systems, 2 Center
More informationHelium-Neon Laser. Figure 1: Diagram of optical and electrical components used in the HeNe laser experiment.
Helium-Neon Laser Experiment objectives: assemble and align a 3-mW HeNe laser from readily available optical components, record photographically the transverse mode structure of the laser output beam,
More information