Ultrafast Laser Science

systemUltrafast sources of laser light continue revolutionizing our understanding of nature on the timescales of the atomic and molecular processes of matter. Direct control over the electric field waveform of an intense and ultrashort laser pulse has enabled the field of attoscience that depends on electron recollision driven by laser fields stronger than the binding field within an atom. Strong field physics directly benefits from frontier research on light source development.

Our group is a leader in laser science and we have, for instance, pioneered CEP-preserving OPCPA which is the prime technique currently being employed worldwide for the next generation of ponderomotively shifted attosecond and x-ray light sources.

Our current focus is on few-cycle and CEP-stable intense sources at high repetition rates beyond the kHz, thereby pushing the limits of average laser power. These sources range from the UV to mid-IR region of the spectrum, they operate with unprecedented average power, encompass cryogenic helium cooling, pulse shaping and various solid-state and fiber-based technologies.

Our latest innovation is a sub-3-cycle and CEP stable OPCPA system at 160 kHz, which reaches 0.2 PW/cm2 intensities with unsurpassed stability and reliability of < 0.5% over 20h. This system enables the mid-IR for experiments across various fields in physics.


OURCONTRIBUTIONS

Mid-Infrared OPCPA

MIR3cycWe present the state-of-the-art of our development of a unique high average power mid-IR OPCPA source. The system delivers passively CEP stable optical pulses with 20 μJ of energy at 3.05 μm center wavelength and duration of 55 fs (5.4 optical cycles). Implementing an all-solid-state self-compression scheme, we produce 38 fs (3.7 optical cycles) duration pulses at 13 μJ and 32 fs (2.9 optical cycles) duration pulses at 3 μJ. In addition, an intrinsically synchronized near-IR output delivering optical pulses with 15 μJ energy, 96 fs duration at 1.62 μm a center wavelength  is derived from the system – this additional output can be used for multi-color experiments or impulsive alignment. The excellent long-term stability of less than 1% RMS power fluctuations over 12.5 hours at 160 kHz makes this source an ideal driver for nonlinear optics experiments in particular mid-IR driven strong-field physics and attoscience.

  1. C. P. Hauri, P. Schlup, G. Arisholm, J. Biegert, and U. Keller, ”Phase-preserving chirped pulse parametric amplification of 17.3 fs pulses from a Ti:Sapphire oscillator”, Opt. Lett. 29, 1 (2004)
  2. O. Chalus, P. Bates, M. Smolarski, J. Biegert, “Mid-IR short-pulse OPCPA with micro-Joule energy at 100 kHz”, Opt. Exp. 17, 3587-3594 (2009)
  3. O. Chalus, A. Thai, P.K. Bates, J. Biegert, “6 cycle mid-IR source with 3.8 μJ at 100 kHz”, Opt. Lett 35, 3204-3206 (2010)
  4. A. Thai, M. Hemmer, P.K. Bates, O. Chalus, J. Biegert, “Sub-250 mrad, Passively Carrier-Envelope Phase Stable Mid-Infrared OPCPA Source at High Repetition Rate”, Opt. Lett. 36, 3918-3920 (2011)
  5. M. Hemmer, A. Thai, M. Baudisch, H. Ishizuki, T. Taira, J. Biegert, “18 μJ energy, 160 kHz repetition rate, 250 MW peak power mid-IR OPCPA”, Chin. Opt. Lett. invited paper, 11, 013202 (2013)
  6. M. Hemmer, M. Baudisch, A. Thai, A. Couairon, J. Biegert, “Self-compression to sub-3-cycle duration of mid-infrared optical pulses in dielectrics”, Opt. Exp. 21, 028095 (2013)
  7. M. Baudisch, H. Pires, H. Ishizuki, T. Taira, M. Hemmer, J. Biegert “Sub-4-optical-cycle, 340-MW peak power, high stability mid-IR source at 160 kHz”, invited paper J. Optics, 14, 094002 (2015)
  8. M. Hemmer, D. Sanchez, M. Jelinek, H. Jelinkova, V. Kubecek, J. Biegert, “2 um wavelength, high energy Ho:YLF chirped pulse amplifier for mid-infrared OPCPA”, Opt. Lett. 40, 451 (2015)
  9. I. Pupeza, D. Sánchez, J. Zhang, N. Lilienfein, M. Seidel, O. Pronin, N. Karpowicz, T. Paasch-Colberg, I. Znakovskaya, V. Pervak, E. Fill, Z. Wei, F. Krausz, A. Apolonski, J. Biegert, “High-power sub-2-cycle mid-infrared pulses at 100 MHz repetition rate”, Nature Phot. 9, 721 (2015)
  10. Sanchez, D. et al. 7-micron, ultrafast, sub-mJ-level mid-IR OPCPA pumped at 2 micron. Optica 3, 147 (2016).

Few-Cycle and 4D Pulse Metrology

hamsterWe demonstrate a simplified arrangement for spatiotemporal ultrashort pulse characterization called Hartmann– Shack assisted, multidimensional, shaper-based technique for electric-field reconstruction. It employs an acousto- optic pulse shaper in combination with a second-order nonlinear crystal and a Hartmann–Shack wavefront sensor. The shaper is used as a tunable bandpass filter, and the wavefronts and intensities of quasimonochromatic spectral slices of the pulse are obtained using the Hartmann–Shack wavefront sensor. The wavefronts and intensities of the spectral slices are related to one another using shaper-assisted frequency-resolved optical gating measurements, performed at particular points in the beam. This enables a three-dimensional reconstruction of the amplitude and phase of the pulse. We present some example pulse measurements and discuss the operating parameters of the device.

  1. W. Kornelis, J. Biegert, J. W. G. Tisch, M. Nisoli, G. Sansone, C. Vozzi, S. De Silvestri, and U. Keller, ”Single-shot kHz ultrashort pulse characterization using SPIDER”, Opt. Lett. 28, 281 (2003)
  2. C. P. Hauri, B. Schäfer, T. Mann, G. Marowski, J. Biegert, and U. Keller, ”Validity of wavefront reconstruction and propagation of ultra-broadband pulses – measured with a Hartmann-shack sensor”, Opt. Lett. 30, 1563-1565 (2005)
  3. F. Bonaretti, D. Faccio, M. Clerici, J. Biegert, P. Di Trapani, “Spatiotemporal Amplitude and Phase Retrieval of Bessel-X pulses using a Hartmann-Shack Sensor”, Opt. Exp. 17, 9804-9809 (2009)
  4. P.K. Bates, O. Chalus,  J. Biegert, “Ultrashort pulse characterisation in the mid-IR”, Opt. Lett. 35, 1377-1379 (2010)
  5. A.S. Wyatt, A. Grün, P.K. Bates, O. Chalus, J. Biegert, I.A. Walmsley, “Accuracy measurements and improvement for complete characterization of optical pulses from non-linear processes via multiple spectral-shearing interferometry”, Opt. Exp. 19, 25355-25366 (2011)
  6. S. Cousin, J.M. Bueno, N. Forget, D.R. Austin, J. Biegert, “Three-dimensional spatio-temporal pulse characterization with an acousto-optic pulse shaper and a Hartmann-Shack wavefront sensor”, Opt. Lett. 37, 3291-3293 (2012)

High Power Lasers and OPCPA

2umA 2-μm wavelength laser delivering up to 39-mJ energy, ∼10 ps duration pulses at 100-Hz repetition rate is reported. The system relies on chirped pulse amplification (CPA): a modelocked Er:Tm:Ho fiber-seeder is followed by a Ho:YLF-based regenerative amplifier and a cryogenically cooled Ho:YLF single pass amplifier. Stretching and compressing are performed with large aperture chirped volume Bragg gratings (CVBG). At a peak power of 3.3 GW, the stability was <1% rms over 1 h, confirming high suitability for OPCPA and extreme nonlinear optics applications.

  1. A. Thai, C. Skrobol, P.K. Bates, G. Arisholm, Z. Major, F. Krausz, S. Karsch, J. Biegert, “Simulations of petawatt-class few-cycle optical-parametric chirped-pulse amplification, including nonlinear refractive index effects”, Opt. Lett. 35, 3471-3473 (2010)
  2. J. Biegert, Philip K. Bates, O. Chalus, “New mid-IR light sources”, IEEE J. Sel. Top. Quant. Electron. – Ultrafast Sci. Technol., invited review paper, 18, 531-540 (2012)
  3. M. Baudisch, M. Hemmer, H. Pires, J. Biegert, “Performance of MgO:PPLN, KTA and KNbO3 for mid-wave infrared broadband parametric amplification at high average power”, Opt. Lett. 39, 5802 (2014)
  4. M. Hemmer, D. Sanchez, M. Jelinek, H. Jelinkova, V. Kubecek, J. Biegert, “2 um wavelength, high energy Ho:YLF chirped pulse amplifier for mid-infrared OPCPA”, Opt. Lett. 40, 451 (2015)
  5. A. Grün, D.R. Austin, S.L. Cousin, J. Biegert, “Three-wave mixing mediated femtosecond pulse compressionin BBO”, Opt. Lett. 40, 4679 (2015)
  6. I. Pupeza, D. Sánchez, J. Zhang, N. Lilienfein, M. Seidel, O. Pronin, N. Karpowicz, T. Paasch-Colberg, I. Znakovskaya, V. Pervak, E. Fill, Z. Wei, F. Krausz, A. Apolonski, J. Biegert, “High-power sub-2-cycle mid-infrared pulses at 100 MHz repetition rate”, Nature Phot. 9, 721 (2015)

CEP Stable Few-Cycle Sources

filament5fsIntense, well-controlled light pulses with only a few optical cycles start to play a crucial role in many fields of physics, such as attosecond science. We present an extremely simple and robust technique to generate such carrier-envelope offset (CEO) phase locked few-cycle pulses, relying on self-guiding of intense 43-fs, 0.84 mJ opti- cal pulses during propagation in a transparent noble gas. We have demonstrated 5.7-fs, 0.38 mJ pulses with an excellent spatial beam profile and discuss the potential for much shorter pulses. Numerical simulations confirm that filamentation is the mechan- ism responsible for pulse shortening. The method is widely applicable and much less sensitive to experimental conditions such as beam alignment, input pulse duration or gas pressure as compared to gas-filled hollow fibers.

  1. C. P. Hauri, P. Schlup, G. Arisholm, J. Biegert, and U. Keller, ”Phase-preserving chirped pulse parametric amplification of 17.3 fs pulses from a Ti:Sapphire oscillator”, Opt. Lett. 29, 1 (2004)
  2. C. P. Hauri, W. Kornelis, F. Helbing, A. Heinrich, A. Couairon, A. Mysyrowicz, J. Biegert, and U. Keller, ”Generation of intense, carrier-envelope phase-locked few-cycle laser pulses through filamentation”, Appl. Phys. B. 79, 673-677 (2004)
  3. A. Couairon, M. Franco, A. Mysyrowicz, J. Biegert, U. Keller, and, ”Pulse self-compression to the single cycle limit by filamentation in a gas with a pressure gradient”, Opt. Lett. 30, 2657-2659 (2005)
  4. F. Silva, P.K. Bates, A. Esteban-Martin, M. Ebrahim-Zadeh, J. Biegert, “Carrier-to-envelope phase-stable, few-cycle pulses at 2.1 μm from a collinear BiB3O6 Optical Parametric Amplifier”, Opt. Lett. 37, 939-935 (2012)
  5. A. Ricci, F. Silva, A. Jullien, S. L. Cousin, D. R. Austin, N. Forget, J. Biegert, R. Lopez-Martens, “Generation of high-fidelity few-cycle pulses at 2μm via cross-polarized wave generation”, Opt. Exp. 21, 9573 (2013)
  6. I. Pupeza, D. Sánchez, J. Zhang, N. Lilienfein, M. Seidel, O. Pronin, N. Karpowicz, T. Paasch-Colberg, I. Znakovskaya, V. Pervak, E. Fill, Z. Wei, F. Krausz, A. Apolonski, J. Biegert, “High-power sub-2-cycle mid-infrared pulses at 100 MHz repetition rate”, Nature Phot. 9, 721 (2015)

Ultrafast Mid- to Long-Wave Infrared Sources

6umWe report on the generation of a 2500 nm bandwidth frequency comb at 6.5 μm central wavelength based on criti- cally phase-matched parametric down-conversion in the nonlinear crystal CdSiP2 (CSP), driven by a compact Er,Tm: Ho fiber laser. The generated ultra-broadband pulses show a transform-limited duration of 2.3 optical cycles and carry up to 150 pJ of energy at a 100 MHz pulse repetition rate. For comparison, the spectrum generated in AgGaS2 (AGS) spans from 6.2 to 7.4 μm at full-width at half-maximum (FWHM) with a pulse energy of 3 pJ. A full 3D non- linear wave propagation code is used for optimization of the noncollinear angle, propagation direction, and crystal thickness.

  1. C. Erny, K. Moutzouris, J. Biegert, D. Kühlke, F. Adler, A. Leitensdorfer, U. Keller, ”Mid-infrared difference-frequency generation of ultrashort pulses tunable between 3.2 and 4.8 um from a compact fiber source”, Opt. Lett. 32, 1138 (2007)
  2. O. Chalus, P. Schunemann, K. Zawilski, J. Biegert, M. Ebrahim-Zadeh, “Optical parametric generation in CdSiP2”, Opt. Lett. 35, 4142-4144, (2010)
  3. F. Silva, D. Austin, A. Thai, M. Baudisch, M. Hemmer, A. Couairon, J. Biegert, “Multi-octave supercontinuum from mid-IR filamentation in bulk”, Nature Commun. 3, 807 (2012)
  4. H. Hoogland, A. Thai,  D. Sánchez, S. Cousin, M. Hemmer M. Engelbrecht, J. Biegert, R. Holzwarth, “All-PM coherent 2.05 µm Thulium/Holmium fiber frequency comb source at 100 MHz with up to 0.5 W average power and pulse duration down to 135 fs”, Opt. Exp. 21, 31390-31394 (2013)
  5. D. D. Hudson, M. Baudisch, D. Werdehausen, B. J. Eggleton, J. Biegert, “1.9 octave supercontinuum generation in a As2S3 step-index fiber driven by Mid-IR OPCPA”, Opt. Lett. 39, 5752 (2014)
  6. I. Pupeza, D. Sánchez, J. Zhang, N. Lilienfein, M. Seidel, O. Pronin, N. Karpowicz, T. Paasch-Colberg, I. Znakovskaya, V. Pervak, E. Fill, Z. Wei, F. Krausz, A. Apolonski, J. Biegert, “High-power sub-2-cycle mid-infrared pulses at 100 MHz repetition rate”, Nature Phot. 9, 721 (2015)
  7. Sanchez, D. et al. 7-micron, ultrafast, sub-mJ-level mid-IR OPCPA pumped at 2 micron. Optica 3, 147 (2016).

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