Parametric Chirped Pulse Amplification System Research Articles

抽运光中ASE噪声对OPCPA信噪比的影响

抽运光中ASE噪声对OPCPA信噪比的影响

Ultrabroadband noncollinear optical parametric amplification with LBO crystal

Ultrabroadband visible noncollinear optical parametric amplification (NOPA) was achieved in an LBO crystal, with a continuum seed pulse generated from a sapphire plate. The spectral bandwidth of the amplified visible pulse was about 200 nm, which can support sub-5 fs pulse amplification. An amplified output of 0.21 microJ with an average gain of about 210 was achieved. This provides, to the best of our knowledge, the first-time demonstration of such broadband amplification with a biaxial nonlinear optical crystal. Both the simulation and experimental results indicate that the LBO has a great potential as nonlinear medium in power amplifier for TW to PW noncollinear optical parametric chirped pulse amplification (NOPCPA) systems.

Bandwidth enhancement for parametric amplifiers operated in chirped multi-beam mode

In this paper we discuss the bandwidth enhancement that can be achieved in multi-Joule optical parametric chirped pulse amplification (OPCPA) systems exploiting the tunability of parametric amplification. In particular, we consider a pair of single pass amplifiers based on potassium-dideuterium-phosphate (DKDP), pumped by the second harmonic of Nd:glass and tuned to amplify adjacent regions of the signal spectrum. We demonstrate that a bandwidth enhancement upto 50% is possible in two configurations; in the first case, one of the two amplifiers is operated near its non-collinear broadband limit; to allow for effective recombination and recompression of the outgoing signals this configuration requires filtering and phase manipulation of the spectral tail of the amplified pulses. In the second case, effective recombination can be achieved simply by spectral filtering: in this configuration, the optimization of the parameters of the amplifiers (pulse, crystal orientation, and crystal length) does not follow the recipes of non-collinear OPCPA.

A hybrid OPCPA/Nd:phosphate glass multi-terawatt laser system for seeding of a petawatt laser

To enhance radiographic abilities on its Z-Accelerator, Sandia National Laboratories is incorporating a petawatt laser system into the existing Z-Backlighter laser facility. As part of this work, a short-pulse laser has been constructed to seed the larger Beamlet type Nd:phosphate glass slab amplifiers. This seed laser consists of an optical parametric chirped pulse amplification (OPCPA) system joined to a Nd:phosphate glass rod amplifier system in order to achieve multi-Joule sub-picosecond operation. The rod amplifier system has been modeled using the Miró code which shows good agreement with the experimental results. This system can achieve focal intensities up to 10 18 W/cm 2 at a repetition rate of once every 20 min and has been applied to produce k-alpha X-rays in copper.

Control of the superfluorescence for compact optical parametric chirped pulse amplification

A compact optical parametric chirped pulse amplification system has been demonstrated, in which a novel double-pass optical parametric chirped pulse amplifier was introduced. The signal was double-pass amplified in the second nonlinear crystal by a long pump pulse, and the signal and pump pulses of each pass were completely phase matched in the plane of the maximum effective nonlinearity. The superfluorescence was markedly suppressed to less than 1% of the total output pulse energy with a total saturation gain of ∼3 × 107 and single pulse energy fluctuation less than 3% rms.

Activation of the Z-petawatt laser at Sandia National Laboratories

To enhance radiographic capabilities on its Z-Accelerator, Sandia National Laboratories is incorporating a petawatt laser system into the existing Z-Backlighter laser facility. A chirped-pulse laser has been constructed to seed the large Beamlet type Nd:Phosphate glass slab amplifiers. This seed laser consists of an optical parametric chirped pulse amplification (OPCPA) system joined to a Nd:Phosphate glass rod amplifier in order to achieve multi-Joule operation. After injection into the main slab amplifiers up to 500 J of chirped pulse energy is achieved. Two compressor options are available for this output: a lower energy compressor for 100TW (50 J/500 fs) operation and a higher energy compressor for 1PW (500 J/500 fs) operation. While the higher energy compressor is under construction, the 100 TW system is now operational and can achieve focal intensities up to 1019 W/cm2.

Numerical simulations for performance optimization of a few-cycle terawatt NOPCPA system

We present a systematic numerical design and performance study of an ultra-broadband noncollinear optical parametric chirped pulse amplification (NOPCPA) system. Using a split-step Fourier approach, we model a three-stage amplifier system which is designed for the generation of 7 fs pulses with multi-terawatt peak intensity. The numerical results are compared with recent experimental data. Several important aspects and design parameters specific to NOPCPA are identified, and the values of these parameters required to achieve optimal working conditions are investigated. We identify and analyze wavelength-dependent gain saturation effects, which are specific to NOPCPA and have a strong influence on the parametric amplification process.

Contrast limitation due to pump noise in an optical parametric chirped pulse amplification system

The contrast ratio of the recompressed output pulses in an optical parametric chirped pulse amplification system can be limited by temporal noise on the pump pulse. We present a simple analysis which can be used to estimate both the contrast ratio of this background noise and the duration of its pedestal. The estimated values compare well quantitatively with values derived using a more accurate computer simulation code.

35 J broadband femtosecond optical parametric chirped pulse amplification system

We report on what is believed to be the first large-aperture and high-energy optical parametric chirped pulse amplification system. The system, based on a three-stage amplifier, shows 25% pump-to-signal conversion efficiency and amplification of the full 70 nm width of the seed spectrum. Pulse compression to 84 fs achieved after amplification indicates a potential of 300 TW pulse power for 35 J amplified pulse energy.

Investigation of the superfluorescence and signal amplification in an ultrabroadband multiterawatt optical parametric chirped pulse amplifier system

We report on theoretical and experimental investigation of the signal and superfluorescence amplification in a 7 TW optical parametric chirped pulse amplifier (OPCPA) system. We demonstrate that the compressed pulse contrast ratio can be improved by using larger seed pulse energies and by careful adjustment of the pump intensity in each amplification stage. Comparison of the measured amplified signal and superfluorescence energies yielded good agreement between calculations and experiments.

A source of 2 terawatt, 2.7 cycle laser pulses based on noncollinear optical parametric chirped pulse amplification

We demonstrate a noncollinear optical parametric chirped pulse amplifier system that produces 7.6 fs pulses with a peak power of 2 terawatt at 30 Hz repetition rate. Using an ultra-broadband Ti:Sapphire seed oscillator and grating-based stretching and compression combined with an LCD phase-shaper, we amplify a 310 nm wide spectrum with a total gain of 3x10(7), and compress it within 5% of its Fourier limit. The total integrated parametric fluorescence is kept below 0.2%, leading to a pre-pulse contrast of 2 x10(-8) on picosecond timescales.

High-dynamic range pulse-contrast measurements of a broadband optical parametric chirped-pulse amplifier

We report on the pulse contrast-ratio characterization of a few-cycle 0.2 TW optical parametric chirped pulse amplifier system operating at 20 Hz. A specially designed third-order correlator was used to characterize and optimize the contrast of the system. We demonstrate that the pulse contrast depends much more on the temporal overlap between the pump and the seed pulse than the shape of the amplified spectrum. The best amplified pulse contrast-ratio was 10-4 at Δt=±25 ps and >10-9 at Δt=±150 ps delays.

Evaluation of Stable Optical Parametric Amplification Involving Temporal Distribution

Numerical evaluation for stable optical parametric amplification has been carried out by involving both temporal distributions and duration differences of pump and seed pulses. It was found that there are some different optimum crystal thicknesses with respect to stable pump-to-seed energy and intensity conversions and optimal reproduction of temporal distribution, which will be practically useful in the design of a practical optical parametric chirped pulse amplification system.

High-energy femtosecond pulse amlification in a quasi-phase-matched parametric amplifier

A new type of solid-state femtosecond amplifier is demonstrated that is based on quasi-phase-matched parametric amplification. Such gain media are different from conventional solid-state amplifiers in that their amplification bandwidths and pump and signal wavelengths can be engineered. Furthermore, high gain is characteristic of parametric amplification, permitting extraction of high energies without the need to resort to multiple-pass configurations. We report a parametric chirped pulse amplification system in which femtosecond pulses from a mode-locked Er-doped fiber laser system are amplified to 1-mJ energies in a single pass by use of a 5-mm-long periodically poled LiNbO(3) (PPLN) crystal. This amplifier is pumped by 5-mJ and 0.5-ns pulses at 786 nm, demonstrating that limitations associated with a low optical-damage threshold for long pump pulses can be overcome because of the high nonlinearity of PPLN and that relatively simple Q -switched lasers can be used with such parametric amplifiers.