Lihuang Lin

Multiterawatt laser system based on optical parametric chirped pulse amplification

A compact multiterawatt laser system based on optical parametric chirped pulse amplification is demonstrated. Chirped pulses are amplified from 20 pJ to 900 mJ by two lithium triborate optical parametric preamplifiers and a final KDP optical parametric power amplifier with a pump energy of 5 J at 532 nm from Nd:YAG-Nd:glass hybrid amplifiers. After compression, we obtained a final output of 570-mJ-155-fs pulses with a peak power of 3.67 TW, which is the highest output power from an optical parametric chirped pulse amplification laser, to the best of our knowledge.

Regenerative amplifier with continuously variable pulse duration used in an optical parametric chirped-pulse amplification laser system for synchronous pumping

A Nd:glass regenerative amplifier has been set up to generate the pumping pulse with variable pulse width for an optical parametric chirped-pulse amplification (OPCPA) laser system. Each pulse of the pulse train from a cw self-mode-locking femtosecond Ti:sapphire oscillator is stretched to approximate to300 ps at 1062 nm to be split equally and injected into a nonlinear crystal and the Nd:glass regenerative amplifier, as the chirped signal pulse train and the seed pulse train of the pumping laser system, respectively. By adjusting the cavity length of the regenerative amplifier directly, the width of amplified pulse could be varied continuously from approximate to300 ps to approximate to3 ns. The chirped signal pulse for the OPCPA laser system and the seed pulse for the pumping laser system come from the same oscillator, so that the time jitter between the signal pulse and the pumping pulse in optical parametric amplification stages could be <10 ps

Blue upconversion luminescence generation in Ce3+: Gd2SiO5 crystals by infrared femtosecond laser irradiation

Blue frequency-upconversion fluorescence emission has been observed in Ce(3+)-doped Gd(2)SiO(5) single crystals, pumped with 120-fs 800 nm IR laser pulses. The observed fluorescence emission peaks at about 440nm is due to 5d?4f transition of Ce3+ ions. The intensity dependence of the blue fluorescence emission on the IR excitation laser power obeys the cubic law, demonstrating three-photon absorption process. Analysis suggested that three-photon simultaneous absorption induced population inversion should be the predominant frequency upconversion mechanism.

Temporal synchronization in optical parametric chirped pulse amplification laser system

The effect of temporal synchronization between the chirped signal pulse and the pumping pulse in an optical parametric chirped pulse amplification laser system is researched theoretically and experimentally. The results show that the gain of optical parametric amplification is sensitive to the temporal synchronization. Therefore, accurate temporal synchronization between the chirped signal pulse and the pumping pulse is essential to obtain high optical parametric amplification gain and stable output from an optical parametric chirped pulse amplification laser. Based on our 16.7-TW/120-fs optical parametric chirped pulse amplification laser system with similar to1-ns pumping pulse duration and <10-ps time jitter between the signal and pumping pulse, the effect of the temporal synchronization on optical parametric chirped pulse amplification is demonstrated. The experimental results agree with the calculation

Broadband high-gain optical parametric chirped- pulse amplification near 780 nm with LBO-I near-degenerate near-collinear phase match

Near-degenerative near-collinear phase-match geometry for broadband optical parametric chirped-pulse amplification (OPCPA) at approximate to 780 nm is calculated in comparison with nondegenerate noncollinear phase-match geometry. In an experiment on LBO-I near-degenerate near-collinear OPCPA, high gain with broad gain bandwidth (approximate to 71 nm, FWHM) at approximate to 780 nm is achieved by using an approximate to 390-nm pumping pulse. The stretched broadband chirped signal pulse near 780 nm is amplified to approximate to 412 mu J with a pumping energy of approximate to 15 mJ, and the total gain is > 3.7 X 10(6), which agrees well with the calculation. For a broadband (covering approximate to 100 nm) chirped signal pulse, the theoretical gain bandwidth has been attained experimentally for the first time. (c) 2005 Society of Photo-Optical Instrumentation Engineers.

Spatial uniformity and its time evolution of linear laser plasmas

The effect of laser illumination conditions on the uniformity of the linear laser plasmas produced is investigated with time-integrated and time-resolved soft x-ray diagnostics. Evident nonuniformities along the line focus resulting from nonuniform laser intensity distributions have been observed with a conventional simple line-focusing technique. Specifically, the nonuniformity of higher charge-state ions is more remarkable than that of lower ones. A uniform linear plasma can be obtained with a new line-focusing technique that produces uniform laser illumination. Nonuniformities under uniform laser illumination are found to occur primarily in the laser heating period. Further development of time-matched and spatial uniform line-focused laser illumination will produce more uniform linear plasmas.

16.7-TW laser system based on optical parametric chirped pulse amplification

A compact 16.7-TW/120-fs laser system based on optical parametric chirped pulse amplification is demonstrated. The chirped pulse was amplified from 50 pJ to 3.1 J. After compression, a final output pulse of 2.0 J/120 fs was obtained.A compact 3.6 TW/155 fs laser system based on optical parametric chirped pulse amplification is demonstrated. The system consists of a femtosecond Ti:sapphire oscillator, a pulse stretcher, a Nd:YAG/Nd:glass amplifier chain as pump laser, an OPA chain and a compressor. The pulses were amplified from 20 pJ to 900 mJ. After compression, a final output of 570 mJ/155 fs was obtained.

A multi‐terawatt OPCPA laser system

The novel optical parametric chirped pulse amplification (OPCPA) scheme is promising for generating ultra‐intense and ultra‐short laser pulse. Based on the OPCPA technique, a compact 3.67TW tabletop laser system was developed with an output of the 570mJ/155fs per‐pulse, which is the highest power output in the existing laser systems based on OPCPA, to the best of our knowledge.

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.

Generation and characterization of femtosecond petawatt Ti:sapphire laser

A Ti:sapphire laser with output of 0.89PW/29.0fs based on the scheme of chirped pulse amplification has been developed. The high gain amplification was achieved in large aperture amplifiers by effective suppression of parasitic lasing.