Research on solid state lasers in Poland; status, applications, prospects

Transcription

1 Research on solid state lasers in Poland; status, applications, prospects WAT Jan K. Jabczyński Institute of Optoelectronics Military University of Technology Warszawa, ul Kaliskiego 1

2 Contents Q-switched Er IOE Ultrafast Warsaw University Fibre Lasers: µm fibre Wroclaw University of Technology - doubled clad pulsed IOE Microchips µm stabilised WUT - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE mj Q-switched oscillator mj eye safe intracavity OPO - Raman lasers QML IOE + CTU Prospects: - CW & Q-switched diode pumped infrared lasers for medicine - hybrid lasers for remote sensing 2

3 3-µm Q-switched Er:YAG laser up 140 mj single shot high rep rate, 20 mj, 90 Output energy[mj] free running Q-switching Supply voltage[v] group of prof. A. Zając: azajac@wat.edu.pl 3

4 Output energy [mj] Upc = 1.35 kv Upc = 2.4 kv Pump energy [J] Pulse output energy vs. pump energy for two values of voltage applied to Pockels cell Hypothetical Er:YAG laser interaction with gelatine. The crater on the left was achieved for free-running pulses, and on the right for Q-switch pulses. Oscilloscope picture of the shortest Q-switch pulse generated by Er:YAG laser. Lower trace laser pulse, upper trace voltage course applied to Pockels cell group of prof. A. Zając: azajac@wat.edu.pl 4

5 Contents Q-switched Er IOE Ultrafast Warsaw University Fibre Lasers: µm fibre Wroclaw University of Technology - double-clad IOE Microchips µm stabilised WTU - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE - 8-mJ Q-switched oscillators - 2-mJ eye safe intracavity OPO - Raman lasers QML IOE + CTU Prospects: - Q-switched Tm lasers for medicine - hybrid lasers for remote sensing 5

6 Femtosecond oscillators at Warsaw University & Institute of Physical Chemistry Ti:Al 2 O 3 multipass amplifier, 10 Hz, 1-2mJ, 60fs, Ti:Al 2 O 3 regenerative amplifier, cryogenics cooling, 1-10kHz, 0.5-2mJ, 80fs, group of prof. Cz. Radzewicz: Czeslaw.Radzewicz@fuw.edu.pl 6

7 Femtosecond NOPCPA s Non collinear Optical Parametric Chirped Pulse Amplifiers Pump beam: II harm Q-switched Nd laser seed beam: stretched pulse of Ti:Al 2 O 3 MLlaser non collinear optical parametric amplification in BBO crystal Aim: > 50 mj, < 30 fs Demonstrated in 1st stage 4-pass amplifier 6 10 Hz after compression 4.5 mj & 30 fs 0.15 TWatt group of prof. Cz. Radzewicz: Czeslaw.Radzewicz@fuw.edu.pl 7

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9 Contents Q-switched Er IOE Ultrafast Warsaw University Fibre Lasers: µm fibre Wrocław University of Technology - double-clad IOE Microchips µm stabilised WTU - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE - 8-mJ Q-switched oscillators - 2-mJ eye safe intracavity OPO - Raman lasers QML IOE + CTU Prospects: - Q-switched Tm lasers for medicine - hybrid lasers for remote sensing 9

10 1.55-µ µm CW fiber lasers CW Tunable, narrow bandwidth fiber lasers 5 0 Moc wyjściowa [dbm] Długość fali [nm] CW multi-wavelength fiber lasers -10 Moc wyjściowa [dbm] -20 I =32 ma d Długość fali [nm] group of prof. K. Abramski: krzysztof.abramski@pwr.wroc.pl

11 1.55-µm ML fiber lasers Światłowodowe lasery erbowe pracy impulsowej Active ML laser ps pulses, frequency muliplying up to GHz Passive ML laser 0.1 ps pulses, coupled solitons, soliton packets -20 Moc optyczna [dbm] nm Długość fali [nm] group of prof. K. Abramski: 11

12 Pulsed double-clad MOFPA system 940 nm 1064 nm S3 y z y z 940 nm 1064 nm x x nonabsorbed pump power Yb-doped LMA fiber S nm S1 amplified signal oscilloscope Nd:YVO laser: f r = khz 3,5 W (85 µj) dla 40 khz 2,5 W (250 µj) dla 10 khz t pulse (min.) = 10,6 ns diaphragm power meter pulse generator polarizer Faraday rotator optical isolator group of prof. A. Zając: azajac@wat.edu.pl λ 2 polarizer HR@1064 nm HT@ 808 nm 12

13 Contents Q-switched Er IOE Ultrafast Warsaw University Fibre Lasers: µm fibre Wroclaw University of Technology - double-clad IOE Microchips µm stabilised WUT - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE - 8-mJ oscillators - 2-mJ eye safe intracavity OPO - Raman lasers QML IOE + CTU Prospects: - Q-switched Tm lasers for medicine - hybrid lasers for remote sensing 13

14 1.06-µm stabilised, tunable microchips for metrology , ,0 110GHz 1 TEC, 2 dioda, 3 GRIN, 4 SSDPL, 5 Brewster plate,, 6 KTP, 7- mirror,, 8 tables (XY), a) SF operation b) temperature change T=19,2 o C up T=24,5 o C T=5,3 o C enables tunig in the range: ν 0 ~ 110GHz@1064nm Laser stabilizowany Nd:YAG/KTP Radiator 1064nm&532nm Lustro dichroiczne 1064nm Sprzęgacz światłowodowy 532nm Fotodetektor (sygnał R) Moduł Peltier'a (Przestrajanie termiczne) Układ automatycznej regulacji Siatka Fotodetektor (sygnał T) 14

15 Microchip IOE Types of microchips developed in last years: µm epitaxial Cr:YAG/Nd:YAG µchips - pigtailed, µm/1.064 µm CW Nd:YVO 4 µchips µm SELG µchips; CW or Q-switched Applications: - interferometry - range finders - remote sensing - special group of dr K. Kopczyński: kkopczynski@wat.edu.pl 15

16 Pigtailed CW SF microchip lasers 532 nm cw 8 mw 1064 nm cw 10 mw 4 mm FSR=500GHz FSR=150GHz 20 mm 90 mm FSR=50GHz group of dr K. Kopczyński: kkopczynski@wat.edu.pl 16

17 Pulse train generation of Cr 4+: YAG/Nd:YAG Repetition rate up to 15 khz Pulse length ns Pulse energy < 6µJ Peak power 3 kw group of dr K. Kopczyński: kkopczynski@wat.edu.pl 17

18 1.5-µm CW generation in Strong Erbium Laser Glass µchip Yb 1.7 x cm -3 Er 0.75 x cm x cm x cm -3 g e n e r o w a n a m o c ś r e d n ia [m W ] SELG - 1 SELG - 2 SELG ,2 0,4 0,6 0,8 1 moc średnia diody padaj ąca na ośrodek aktywny [W] P out = 150 mw cw η = 0.16, P out = 300 mw q-cw η = group of dr K. Kopczyński: kkopczynski@wat.edu.pl 18

19 1.34-µm Nd:YAG/V:YAG microchips Nd:YAG gain medium V:YAG saturable absorber Undoped YAG for better thermal management Mirrors are deposited directly on crystal end faces PUMP BEAM YAG Nd:YAG group of prof.h. Jelinkova: 19

20 1.34-µm Nd:YAG/V:YAG microchips; summary t E out P peak P mean L rez CW 6.2 ns 37 µj 6 kw 420 mw 16.7 mm Higher pulse energy and laser mean power Stable linearly polarized output emission at 1338 nm CW 1.7 ns 15 µj 9 kw 120 mw 4.7 mm Shorter pulse length and higher peak power group of prof.h. Jelinkova: Hjelin@trojafjfi.cvut.cz 20

21 Contents Q-switched Er IOE Ultrafast Warsaw University Fibre Lasers: µm fibre Wroclaw Technical University - double-clad IOE Microchips µm stabilised WTU - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE - 8- mj, Q-switched 2.1-ns oscillator - 2- mj eye safe intracavity OPO - intracavity Raman lasers QML IOE + CTU Prospects: - Q-switched Tm lasers for medicine - hybrid lasers for remote sensing 21

22 Side pumped Nd:YAG slab oscillator intracavity Raman lasers KTP intracavity OPO resonator up to 2 mj 1.57 µm Nd:YAG slab 600-W qcw FAC LD stack Pockels cell (or Cr:YAG) Q-switched) 8 mj / 2.1 ns, 50 µm 4 mj / 2 ns, µm group of prof. Jabczyński, jjabczynski@wat.edu.pl 22

23 Crystals for Raman lasers BaWO 4 KGd(WO 4 ) 2 (KGW) Dimensions 6 mm x 6 mm x 33 mm 4 mm x 4 mm x 40 mm Raman shift 925 cm cm -1 (E C 2 ) 768 cm -1 (E//C 2 ) Raman gain (1.06 µm) 39.4 cm/gw 18.6 cm/gw group of prof. Jabczyński, jjabczynski@wat.edu.pl group of prof.h. Jelinkova: Hjelin@trojafjfi.cvut.cz 23

24 Nd:YAP/KGW Raman triangle laser D Nd:YAP Cr:YAG KGW 1.St Stokes E//C µm E C µm Raman pulse length ~1 ns Raman output energy 90 µj Peak power 90 kw Mean power 1.3 mw KGW E// //C µm µm KGW E C µm µm 24

25 Nd:YAG vs. Nd:YAP Raman triangle-slab lasers Wavelength (first Stokes) Energy Nd:YAG/BaWO µm 1.46 mj Nd:YAP/BaWO µm 165 µj Pulse length 3.5 ns 1.7 ns 25

26 Contents Q-switched Er IOE Ultrafast Warsaw University Fiber Lasers: - Mode Locked Wroclaw Technical University - IOE Microchips µm stabilised WTU - green, eye safe MUT µm V:YAG Q-switched CTU & CRYTUR Side pumped, multi-wavelength IOE - 8-mJ oscillators - 2-mJ eye safe intracavity OPO - Raman lasers QML IOE + CTU Prospects: - Q-switched Tm lasers for medicine - hybrid lasers for remote sensing 26

27 Types of QML lasers Passive QML: - bulk saturable absorbers (Cr 4+ :YAG, V 3+ :YAG) - multi quantum wells saturable absorbers (MQW-SA) - Stankov s nonlinear mirror + Q-switch Active QML: - AO Mode Locker + EO Q-switch - AO Q-switch Mode Locker (AO-QML) group of prof. Jabczyński, jjabczynski@wat.edu.pl 27

28 AO-QML Nd:YVO 4 laser pumped by 20 W FCB 4 3 P cw = ( P ) T oc = 66% ; best case P qcw = (P ) Z-cavity, 40.6 MHz, R=1000, R=1000 Output Power [ W ] Pump Power [ W ] Output power vs. Pump power AOM LDBS 25W laser diode with beam shaper, AM- 0.3% Nd:YVO 4, AOM- acousto-optic cell, cavity frequency match to radio frequency c/2l cav =40.7 MHz, L cav = 3690 mm group of prof. Jabczyński, jjabczynski@wat.edu.pl 28

29 Results of AO-QML Nd:YVO 4 laser Best case: - 3 W average 30 khz rep.rate µj QML envelope; ns FWHM - 30 µj ML pulse with τ < 1 ns FWHM 1GHz DSA 601 scope 500 MHz TDS3052 scope group of prof. Jabczyński, jjabczynski@wat.edu.pl 29

30 MQW-SA-QML side pumped Nd:YAG slab laser M2 A LD M1 r=1m Nd:YAG M3 MQW 758D R= 50 % (40%) Pump: 600-W qcw 123 A, 33 Hz, 200 us gain medium : single bounce triangle Nd:YAG slab V-type cavity of 140 cm E out = 2 mj, 6 pulses, 95 ps, 0.8 mj/single pulse 0.65 mj, 3 pulses, 65 ps, 0.2 mj/ single pulse group of prof. Jabczyński, jjabczynski@wat.edu.pl group of prof. V. Kubecek, kubecek@troja.fjfi.cvut.cz 30

31 MQW-SA-QML side pumped Nd:YAG slab laser SH intensity Shortest 3-pulse enevelope translation [mm] Autocorrelation trace Passive negative feedback E out = 2 mj, 6 pulses, 95 ps, 0.8 mj/single pulse 0.65 mj, 3 pulses, 65 ps, 0.2 mj/ single pulse group of prof. Jabczyński, jjabczynski@wat.edu.pl group of prof. V. Kubecek, kubecek@troja.fjfi.cvut.cz 31

32 WAT Summary & Prospects R-D focused on definite applications 1.9-µm diode pumped CW & Q-switched Tm laser for medicine: preliminary results CW: up to 6 W Q- switched: 2 mj / 15 ns, 300 Hz Diode pumped CW & Q-switched Er laser for medicine Hybrid eye safe Q-switched lasers for special applications - tunable Q-switched Ho:YAG laser pumped by Tm fiber laser - Q-switched Er:YAG laser pumped by Er fiber laser 32

33 WAT Acknowledgment to: prof. H. Jelinkova, Czech Technical University, Prague prof. V. Kubecek, Czech Technical University, Prague dr K. Nejezchleb, CRYTUR, Turnov, Czech Republik prof. Cz. Radzewicz, Warsaw University prof. K. Abramski, Wrocław University of Technology prof. A. Zając, Military University of Technology dr K. Kopczyński, Military University of Technology 33