On Optical Parametric Chirped Pulse Amplification Research Articles

Femtosecond mid-IR optical vortex laser based on optical parametric chirped pulse amplification

A femtosecond mid-infrared optical vortex laser can be used for high harmonic generation to extend cutoff energy to the kilo-electron-volt range with orbital angular momentum, as well as other secondary radiations. For these, we demonstrate a high-energy femtosecond 4 μm optical vortex laser based on optical parametric chirped pulse amplification (OPCPA) for the first time. The optical vortex seed is generated from a femtosecond 4 μm laser by a silicon spiral phase plate with the topological charge l of 1 before the stretcher. Through using a two-stage collinear OPCPA amplifier, the chirped vortex pulse is amplified to 12.4 mJ with 200 nm full width at half-maximum bandwidth. After compression, the vortex laser pulse with 9.53 mJ, 119 fs can be obtained. Furthermore, the vortex characteristics of the laser beam are investigated and evaluated. This demonstration can scale to generate a higher-peak-power vortex mid-IR laser and pave a new way for high field physics.

Femtosecond Laser Pulses Amplification in Crystals

This paper describes techniques for high-energy laser pulse amplification in multi-PW femtosecond laser pulses. Femtosecond laser pulses can be generated and amplified in laser media with a broad emission spectral bandwidth, like Ti:sapphire crystals. By chirped pulse amplification (CPA) techniques, hundred-Joule amplified laser pulses can be obtained. Multi-PW peak-power femtosecond pulses are generated after recompression of amplified chirped laser pulses. The characteristics and problems of large bandwidth laser pulses amplification in Ti:sapphire crystals are discussed. An alternative technique, based on optical parametric chirped pulse amplification (OPCPA) in nonlinear crystals, is presented. Phase-matching conditions for broad bandwidth parametric amplification in nonlinear crystals are inferred. Ultra-broad phase matching bandwidth of more than 100 nm, able to support the amplification of sub-10 fs laser pulses, are demonstrated in nonlinear crystals, such as Beta Barium Borate (BBO), Potassium Dideuterium Phosphate (DKDP), and Lithium Triborate (LBO). The advantages and drawbacks of CPA amplification in laser crystals and OPCPA in nonlinear crystals are discussed. A hybrid amplification method, which combines low-medium energy OPCPA in nonlinear crystals with high energy CPA in large aperture laser crystals, is described. This technique is currently used for the development of 10-PW laser systems, with sub-20 fs pulse duration and more than 1012 intensity contrast of output femtosecond pulses.

Analysis and construction status of SG-II 5PW laser facility

We present a recent progress of the SG-II 5PW facility, which designed a multi-petawatt ultrashort pulse laser based on optical parametric chirped-pulse amplification (OPCPA). The prior two optical parametric amplifiers have been accomplished and chirped pulses with an energy of 49.7 J and a full-width-at-half-maximum (FWHM) spectrum bandwidth of 85 nm have been achieved. In the PW-scale optical parametric amplification (OPA), with the pump pulse that has an energy of 118 J from the second harmonic generation of the SG-II 7th beam, the pump-to-signal conversion efficiency is up to 41.9%, which to the best of our knowledge is the highest among all of the reported values for OPCPA systems. The compressed pulse is higher than 37 J in 21 fs (1.76 PW), and the focal spot is ${\sim}10~\unicode[STIX]{x03BC}\text{m}$ after the closed-loop corrections by the adaptive optics. Limited by the repetition of the pump laser, the SG-II 5PW facility operates one shot per hour. It has successfully been employed for high energy physics experiments.

Conceptual design of sub-exa-watt system by using optical parametric chirped pulse amplification

A 50 PW ultrahigh-peak-power laser has been conceptually designed, which is based on optical parametric chirped pulse amplification (OPCPA). A 250 J DPSSL and a flash- lamp-pumped kJ laser are adopted as new repeatable pump source. The existed LFEX-laser with more than ten kilo joules are used in the final amplifier stage and the OPCPA with the 2x2 tiled pump beams in random phase has been proposed with several ten centimeter aperture. A pulse duration of amplified pulses is set at less than 10 fs. A broadband OPCPA with ∼500 nm of the gain spectral width near 1 μm is required. A partially deuterated KDP (p-DKDP) crystal is one of the most promising nonlinear crystals and our numerical calculation ensured such ultra-broad gain width. p-DKDP crystals with several deuteration ratio have been successfully grown.

Ultrafast midinfrared laser system for enhanced self-amplified spontaneous emission applications

Of particular interest to x-ray free-electron laser light source facilities is the enhanced self-amplified spontaneous emission (ESASE) technique. ESASE requires an ultrafast (20--50 fs), high peak power, high repetition rate, reliable laser system working in the midinfrared spectral range ($\ensuremath{\ge}2\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$). These requirements can be met by a novel ultrafast midinfrared laser system based on optical parametric chirped-pulse amplification (OPCPA). OPCPA is a technique ideally suited for production of ultrashort laser pulses at the center wavelength of $2\text{ }\text{ }\ensuremath{\mu}\mathrm{m}$. Some of the key features of OPCPA are the wavelength agility, broad spectral bandwidth, and negligible thermal load. The ESASE-compatible laser technology analysis and the preliminary OPCPA simulation results are presented.

Generation and amplification of dual-color femtosecond pulses by a noncollinear optical parametric up-conversion process

Noncollinear optical parametric up-conversion generation and amplification are realized in a thick β-barium borate (BBO) crystal, and a couple of visible femtosecond up-conversion laser pulses can be achieved by a femtosecond pulse at 800 nm as the pump sources. The theoretical and experimental results indicate that there exist phase-matching conditions for dual-color noncollinear parametric up-conversion generation and amplification, and their wavelengths can be tuned by rotating the BBO crystal. This parametric up-conversion generation and amplification can be attributed to three and five-wave mixing in a thick BBO crystal, and it shows the potential application on optical parametric chirped pulse amplification (OPCPA) to generate multi-color ultraviolet or visible femtosecond laser pulses pumped directly by femtosecond fundamental laser pulses without frequency-doubling or tripling.

Multi-millijoule, nonlinear preamplifier for high intensity femtosecond Yb:YAG chirped-pulse amplification lasers at 1030 nm

We report the highest energy broadband laser pulses at a center wavelength of 1030 nm based on optical parametric chirped-pulse amplification (OPCPA). We have demonstrated amplification of 1030 nm femtosecond laser pulses from a broadband Yb oscillator to over 6.5 mJ with a total gain of greater than 107 achieved in a single pass through only 56 mm of gain material at a 10 Hz repetition rate. The amplified spectral bandwidth of 10.8 nm affords recompression to a 230 fs pulse duration following amplification. As an alternative to the regenerative amplifier (RA) this system is one of the more promising candidates for realizing compact, high intensity, direct diode-pumped, high repetition rate femtosecond Yb:YAG chirped-pulse amplification (CPA) in laser systems.

Mid-IR short-pulse OPCPA with micro-Joule energy at 100kHz

We present a novel mid-IR source based on optical parametric chirped pulse amplification (OPCPA) generating 96 fs pulses (9.0 cycles) at 3.2 mm with an energy of 1.2 microJ, at a repetition rate of 100 kHz. The amplified spectrum supports a minimum Fourier transform limited pulse duration of 45 fs, or 4.2 cycles. Our use of OPCPA allows the direct amplification of few-cycle pulses at this mid-IR wavelength, and is inherently scalable to higher energies. The seed source for the system is based on difference frequency generation (DFG) between two outputs of the same fibre laser: this source is expected to be intrinsically CEP stable.

Optical parametric chirped-pulse amplification source suitable for seeding high-energy systems

A short-pulse source based on optical parametric chirped-pulse amplification (OPCPA) technology has been developed with properties that make it a suitable seed for a high-energy OPCPA system. This source generated a diffraction-limited pulse at 910 nm with a full bandwidth of > 165 nm and a spectrum having a transform-limited pulse duration of less than 15 fs. The technique has potential for generating bandwidths > 200 nm and pulse durations < 10 fs.

High-contrast, high-intensity laser pulse generation using a nonlinear preamplifier in a Ti:sapphire laser system

We report a high-contrast, high-intensity Ti:sapphire chirped-pulse amplification system that incorporates a nonlinear preamplifier based on optical parametric chirped-pulse amplification (OPCPA). By cooling the Ti:sapphire crystal in the final amplifier down to 77 K, the chirped-pulses are amplified to 2.9 J at a 10 Hz repetition rate without a thermal lensing effect. Pulse compression down to 19 fs duration obtained after amplification indicates a peak power of 80 TW. With the OPCPA, the temporal contrast is significantly improved to better than 7x10(-9) in a few picoseconds interval prior to the main laser pulse.

Development of high-power OPCPA laser at 1064 and 780 nm

A compact 10-TW/100-fs level ultrashort-pulse and ultra-intense laser system at 1064 nm based on optical parametric chirped pulse amplification (OPCPA) scheme is described, at which the pump and seed for the optical parametric amplification (OPA) process is optically synchronized. We investigated the output stability and the conversion efficiency of the system. Moreover, a design toward higher peak power output is given and an optically synchronized amplifier based on the concept of OPCPA at 800 nm is preliminarily explored.