OPCPA System Research Articles

Multi-μJ, CEP-stabilized, two-cycle pulses from an OPCPA system with up to 500 kHz repetition rate

We present a two-stage OPCPA system based on a Ti:sapphire seed and a thin-disk regenerative amplifier producing compressed pulse energies of more than 3 μJ and durations of less than 6 fs at a high repetition rate of 143 kHz. In combination with the obtained CEP stability and the repetition rate scalability between 100 and 500 kHz the system forms an ideal tool for high field and phase sensitive spectroscopic experiments.

High-fidelity front-end for high-power, high temporal quality few-cycle lasers

A 80 μJ, 6 fs, CEP-stable high-contrast injector is demonstrated. The device relies on standard pulse post-compression in hollow-core fiber followed by a temporal filter based on cross-polarized wave generation. Pulses with a Gaussian spectrum over 350 nm, centered at 750 nm, are generated. Temporal measurements show that the contrast of the few-cycle pulses is enhanced on a femtosecond and picosecond time scale. The carrier-envelope phase stability is preserved (0.3 rad RMS). These performances make the system an ideal seed laser for high-power, high-contrast OPCPA systems.

High average and peak power few-cycle laser pulses delivered by fiber pumped OPCPA system

We report on a high power optical parametric amplifier delivering 8 fs pulses with 6 GW peak power. The system is pumped by a fiber amplifier and operated at 96 kHz repetition rate. The average output power is as high as 6.7 W, which is the highest average power few-cycle pulse laser reported so far. When stabilizing the seed oscillator, the system delivered carrier-envelop phase stable laser pulses. Furthermore, high harmonic generation up to the 33(th) order (21.8 nm) is demonstrated in a Krypton gas jet. In addition, the scalability of the presented laser system is discussed.

10-mJ optically synchronized CEP-stable chirped parametric amplifier at 1.5 μm

We demonstrate the generation of 10-mJ 1.5-μm few-cycle pulses from a 4-stage OPCPA system. The system is based on a fusion of femtosecond DPSS Yb technology and a picosecond Nd:YAG pump laser. In a first preliminary filamentation experiment in argon at 5 atm, we observe significant spectral broadening of the recompressed multi-mJ 1.5-μm pulses. The filamentation output spectrum supports the generation of 8 fs pulses equivalent to sub-to-cycle pulses at 1.5 μm. We foresee that our terawatt-peak-power sub-to-cycle pulse source will open the door to exciting new experiments in attosecond high-field science in the near future.

Few-cycle OPCPA system at 143 kHz with more than 1 μJ of pulse energy

We present an OPCPA system delivering 8.8 fs (3.3 optical cycles) pulses with 1.3 microJ of energy at 143 kHz repetition rate. Pump and seed for the parametric amplification are simultaneously generated by a broadband Ti:sapphire oscillator. The spectral components beyond 1000 nm are separated and amplified in an Yb:YAG thin-disk regenerative amplifier. The pulses are characterized using autocorrelation and SPIDER apparatus. With a pulse peak power of nearly 130 MW, the system is well-suited for future table top strong field experiments.

An all fiber multi-laser pulse generation system

We demonstrate an all fiber multi-laser pulse generation system that can output broadband chirped pulse, nano-second shaped pulse and narrowband pump pulse for optical parametric chirped pulsed amplifiers system with precise synchronization. Yb3+-doped fiber mode-locked laser and single longitudinal oscillator are used as the optical source for the fiber system. The ultra-short pulse train generated from the mode locked fiber laser was split into two beam-lines and both were chirp-stretched to 0.9 ns. One of them was directly amplified to a magnitude of 10 μJ to provide the high-energy petawatt laser facility with seed pulse. The other was tailored by a 1.2 nm bandwidth filter to form a 140 ps unit pulse. It was then stacked in a fiber stacker and formed a 2.3 ns arbitrarily shaped pulse. The shaped pulse was amplified to 10 μJ to provide seed pulse for the pellet compression. Simultaneously, we sampled part of the ultra-short pulse train from the mode locked laser. The sampled pulse train was converted to electrical signal and phase-locked to generate trigger pulse that precisely synchronized with the mode locked pulse for an amplitude modulator. The continuous-wave laser generated from the fiber single longitudinal oscillator was tailed by the amplitude modulator and then amplified to provide seed pulse for the OPCPA system. The output of the fiber system can switch between different kinds of pulses with flexibility according to the physical experimental requirement.

Compact fiber amplifier pumped OPCPA system delivering Gigawatt peak power 35 fs pulses

We report on a compact Gigawatt peak power OPCPA system which is pumped by the second harmonic of an Yb-doped fiber amplifier and seeded by a cavity dumped Ti:Sapphire oscillator. Picosecond pump pulses for the OPCPA are generated by spectral filtering and directly amplified to 1 mJ pulse energy in several fiber amplifiers, without the need of chirped pulse amplification. Since no stretcher and compressor is required, the pump laser is very compact and easy to operate. The two stage optical parametric amplifier delivers 35 fs pulses with 53 microJ pulse energy and 1.1 GW peak power at 40 kHz repetition rate. Additionally, the scaling potential of this approach is discussed.

Conceptual design of laser fusion reactor KOYO-fast

A conceptual design of the laser fusion reactor KOYO-F based on the fast ignition scheme is reported including the target design, the laser system and the design for chamber. A Yb-YAG ceramic laser operated at 200K is the primary candidate for the compression laser and an OPCPA system is the one for the ignition laser. The chamber is basically a wet wall type but the fire position is vertically off-set to simplify the protection scheme of the ceiling. The target consists of foam insulated, cryogenic DT shells with a LiPb, reentrant guide-cone.