Nonlinear Optics (WiSe 2016/17) Lecture 9: December 16, 2016 Continue 9 Optical Parametric Amplifiers and Oscillators

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1 Nonlinear Optics (WiSe 2016/17) Lecture 9: December 16, 2016 Continue 9 Optical Parametric Amplifiers and Oscillators 9.10 Passive CEP-stabilization in parametric amplifiers Active versus passive CEP-locking Generation of CEP-stable pulses from an OPA: - CEP-stable IR pulses from hybrid type-ii OPCPA/filamentation system - OPCPA of a 2-μm seed pulse obtained by intrapulse DFG - Dual-chirped infrared optical parametric amplification (DC-OPA) - CEP-stable mid-ir and THz waveforms - Parametric sub-cycle optical waveform synthesizers Largely follows the review paper of Cerullo et al., Few-optical-cycle light pulses with passive carrier-envelope phase stabilization, Laser Photonics Rev. 5, (2011) 1

2 9.10 Passive CEP-stabilization in parametric amplifiers Active versus passive CEP-locking Active carrier-envelope phase locking pulse train emitted from mode-locked oscillator femtosecond frequency comb 2

3 enabling technology JOSA B 27, B51 (2010): - ultrahigh-precision spectroscopy Nature 416, 233, (2002) - optical clocks Science 306, 1318 (2004)

4 Active CEP-stabilization of chirped-pulse amplifier 1. Measure n CEO by a nonlinear interferometer 2. Stabilize n CEO by an active high-bandwidth feedback on the laser oscillator (fast loop) to n * CEO 3. Pick pulses at the integer fraction of n * CEO 4. After amplification, measure CEP φ of pulses by a single-shot nonlinear interferometer and use an additional feedback loop (slow loop) to correct for fluctuations induced by the amplification process (and optionally external spectral broadening, e.g., in a hollow-core fiber compressor) and lock CEP to φ. 4

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7 Phase sum rules of nonlinear processes 7

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11 Passive stabilization of the CEP 11

12 Passive stabilization of the CEP 12

13 Passive stabilization of the CEP 13

14 Generation of CEP-stable pulses from an OPA CEP-stable idler phase-repeating OPA CEP-stable idler 14

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16 CEP-stable pulses from a visible NOPA A. Baltuška, T. Fuji, and T. Kobayashi, Phys. Rev. Lett. 88, (2002) 16

17 A. Baltuška, T. Fuji, and T. Kobayashi, Phys. Rev. Lett. 88, (2002) 17

18 CEP-stable ultrabroadband pulses from cascaded OPAs C. Manzoni et al., Appl. Phys. Lett. 90, (2007) 18

19 CEP-stable ultrabroadband pulses from cascaded OPAs C. Manzoni et al., Appl. Phys. Lett. 90, (2007) 19

20 CEP-stable ultrabroadband pulses from cascaded OPAs C. Manzoni et al., Appl. Phys. Lett. 90, (2007) 20

21 CEP-stable IR pulses from hybrid type-ii OPCPA/ filamentation system building blocks: (i) self-cep-stabilized 1.5-μm frontend: CEP-stable collinear type-i BBO OPA + narrowband type-ii KTP OPA (ii) type-ii KTP OPCPA based on picosecond Nd:YAG technology (iii) pulse self-compression by filamentation in noble gases motivation for architecture: (a) near-degenerate type-i OPAs have worst possible quantum defect for signal (b) even though group-velocity-matched OPAs deliver ultrabroad output spectra (>200 nm), quality of resulting compressed pulses most often remains poor due to intrinsically steep slopes of the parametrically amplified spectra (c) more narrowband amplification has the advantage of optimizing the spectral brightness of the signal (suppression of parametric superfluorescence) (d) when scaling the pulse energies of type-i OPAs to the mj-level, cascaded FWM can cause unwanted losses due to parasitic self-diffraction. O. D. Mücke et al., Opt. Lett. 34, (2009) O. D. Mücke et al., Opt. Lett. 34, (2009) 21

22 O. D. Mücke et al., Opt. Lett. 34, (2009) O. D. Mücke et al., Opt. Lett. 34, (2009) 22

23 OPCPA of a 2-μm seed obtained by intrapulse DFG ~40 fs K.-H. Hong et al., Opt. Lett. 39, 3145 (2014) K.-H. Hong et al., Opt. Express 19, (2011) J. Moses et al., Opt. Lett. 34, 1639 (2009) at MPQ: T. Fuji et al., Opt. Lett. 31, 1103 (2006); X. Gu et al., Opt. Express 17, 62 (2009); Y. Deng et al., Opt. Lett. 37, 4973 (2012). 23

24 Dual-chirped IR optical parametric amplification Q. Zhang et al., Opt. Express 19, (2011) 24

25 Dual-chirped IR optical parametric amplification OPCPA DC-OPA Q. Zhang et al., Opt. Express 19, (2011) 25

26 Dual-chirped IR optical parametric amplification Y. Fu et al., Opt. Lett. 21, (2015) Y. Fu et al., J. Opt. 17, (2015) 26

27 Dual-chirped IR optical parametric amplification 30%-40% total (=s+i) efficiency pump at 100-mJ level signal compressed to 27fs self-cep-stabilized idler good prospects for scaling to hundred-mj-level and even J-level Y. Fu et al., Opt. Lett. 21, (2015) Y. Fu et al., J. Opt. 17, (2015) 27

28 CEP-stable mid-ir and THz waveforms CEP controlled by Dt OPA1,2 seeded by same WL type-ii DFG in GaSe or AgGaS 2 A. Sell et al., Opt. Lett. 33, 2767 (2008) C. Manzoni et al., Opt. Lett. 35, 757 (2010) 28

29 CEP-stable mid-ir and THz waveforms 800-µm AgGaS 2 all others 140-µm GaSe A. Sell et al., Opt. Lett. 33, 2767 (2008) C. Manzoni et al., Opt. Lett. 35, 757 (2010) 29

30 Coherent parallel sub-cycle waveform synthesis High-energy multi-color pulses (ultrabroad spectrum for each pulse) Extremely precise dispersion control over the whole bandwidth Relative timing must be locked to sub-cycle precision Each pulse must be phase stable at the synthesis point C. Manzoni et al., Laser Photonics Rev. 9, 129 (2015)

31 Parametric sub-cycle optical waveform synthesizers >2-octave-wide waveform synthesis from OPAs at the multi-mj level and at 1 khz WLG seed split into 3 wavelength channels and amplified in 3 OPA stages each 3 channels are individually compressed and coherently recombined relative timing is tightly locked using balanced optical cross-correlators (BOCs) O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015) C. Manzoni et al., Laser & Photonics Rev. 9, (2015) NOPA: noncollinear OPA; DOPA: degenerate OPA 31

32 Self-CEP-stabilized white-light seed spectrum pump: CEP-stable SH of OPA idler, 3-mm YAG 1.06 µm 1-10 nj

33 Parametric sub-cycle optical waveform synthesizers VIS NOPA NIR DOPA IR DOPA 0.17 mj signal mj signal 1.7 mj octave-spanning signal 20% (0.8 mj pump) pump-signal conversion efficiency 12-15% (1.7 mj pump) pump-signal conversion efficiency 22% (7.7 mj pump) pump-signal conversion efficiency TL 5.6 fs TL 5.2 fs TL 5.2 fs 2.9 optical l c =573nm 2.1 optical l c =750nm 1.1 optical l c =1.4um O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015) 33

34 Precise dispersion management of waveform synthesizer In the design of the compression scheme we compensate the dispersion of YAG, BBOs, mirrors substrates, vacuum chamber windown and propagation through air - match duration of seed pulses to pump pulses in each stage - avoid/suppress buildup of detrimental superfluorescence in amplification chain - avoiding B-integral problems in final beam recombiner and chamber window by doing the final recompression inside chamber O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015)

35 Reflectivity (%) Group Delay (fs) >2-octave precision dispersion control Ultrabroadband dual adiabatic matching (DAM) DCM pair for final compression inside experimental chamber, extending over >2 octaves, with >90% reflectivity Ave GD (Calculation) Ave GD (Measurement) 0.72mm SiO mm ZnSe Wavelength (µm) S.-H. Chia et al., Optica 1, 315 (2015)

36 Parametric sub-cycle optical waveform synthesizers O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015) 36

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38 Parametric sub-cycle optical waveform synthesizers recompressed all channels simultaneously close to TL at synthesis point flexible dispersion compensation scheme can be used at multi-mj level O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015) 38

39 Parametric sub-cycle optical waveform synthesizers 3 possible synthesized E(t), computed form the FROG-retrieved pulses (2 nd stage) O. D. Mücke et al., IEEE J. Sel. Top. Quantum Electron. 21, (2015) 39

40 long-l OPA Sub-cycle relative timing lock using a balanced optical cross-correlator (BOC) short-l OPA BOC S.-W. Huang et al., Nature Photonics 5, 475 (2011) C. Manzoni et al., Opt. Lett. 37, 1880 (2012) T. R. Schibli et al., Opt. Lett. 28, 947 (2003) (original demonstration)

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42 relative delay (fs) Timing lock between VIS NOPA and IR DOPA timing jitter spectral density (fs 2 /Hz) relative delay (fs) 30 open loop closed loop (a) 1.0 rms 360 as (b) "I" feedback "PI" feedback optimization time (second) time (ms) overall jitter 360 as (c) lock jitter 130 as frequency (Hz) S. Fang et al., CLEO-EU 2015, paper CG_P_4

43 Phase lock between VIS NOPA and IR DOPA complete locking in progress 43