Gennady I. Freidman

200 TW 45 fs laser based on optical parametric chirped pulse amplification

200 TW peak power has been achieved experimentally using a Cr:forsterite master oscillator at 1250 nm, a stretcher, three optical parametrical amplifiers based on KD*P (DKDP) crystals providing 14.5 J energy in the chirped pulse at 910 nm central wavelength, and a vacuum compressor. The final parametrical amplifier and the compressor are described in detail. Scaling of such architecture to multipetawatt power is discussed.

100-TW Femtosecond Laser Based on Parametric Amplification

In experiments on the parametrical amplification of femtosecond pulses in wide-aperture DKDP crystals, a power of more than 100 TW has been reached, which is much higher than the record level achieved in such lasers. The energy efficiency obtained for the parametric amplifier is equal to 27%. The energy of a 72-fs pulse is equal to 10 J.

Parametric amplification of chirped laser pulses at 911-nm and 1250-nm wavelengths

The analysis of tuning characteristics for parametric amplification in KD*P has shown that the application of KD*P crystals may considerably enhance the possibilities of certain optical parametric amplifiers of both terawatt and petawatt level. For instance, at pumping with a wavelength of (lambda) 3 equals 0.527 micrometers , which is most promising for the creation of such systems, the KD*P-based amplifiers may work far from the degenerate mode, e.g., at (lambda) s- 0.911 micrometers and (lambda) i-1.25 micrometers . For operation at these wavelengths there are currently master oscillator of femtosecond pulses with pulse duration of up to 30 fs. In this paper elements of the system are discussed, and their parameters are optimized.

Multicascade boradband optical parametric chirped pulse amplifier based on KD*P crystals

We have experimentally demonstrated the existence of super-broadband non-degenerated phase matching for a signal with a wavelength of 911 nm in KD*P crystal pumped with wavelength of 527nm. Parametric amplification coefficient of more than 107 in three cascades is achieved. This resulted in pulse energy 10mJ at the output of third cascade. It is shown that in the KD*P crystal chirped pulses of conventional femtosecond sources (a Ti:Sa laser at 911 nm and a Cr:forsterite laser at 1250 nm) can be amplified up to the level that ensures multipetawatt power after compression.

Spectroscopy of supersmall absorption using the technique of a phase-contrast thermal lens

The problem of measuring supersmall light absorption in materials led to the development of a high-sensitivity optothermal laser technique, thermal lens and interferometer technique being the most widely-known. An optimum combination of the two above methods has been implemented where high sensitivity of optothermal phase-contrast technique (which reached for liquid media 10 -9 cm -1 at the pump energy 3 J) was demonstrated. The technique suggested here is quite competitive with other optothermal methods due to its simplicity of performing, absorption linearity of the measured signal and independence of the signal on absorption at the windows of the cell containing the medium under investigation.

Development of eye-safe IR lidar emitter and detector technologies

Lidar systems developed over the last decade have demonstrated impressive results when applied to the detection of specific volatile chemicals. MOst of these systems are limited to a single wavelength or, at best, a narrow wavelength band. Exceptions are DIAL systems, CO2 lidars, and dye laser sources. Currently under development at INEEL and PASSAT Ltd. are technologies that convert Nd:YAG laser energy to the 8-11 micrometers band with an output of 20 millijoules/pulse or higher. Wavelength shifting is accomplished using a tunable optical parametric oscillator and amplifier, and stimulated Raman scattering cells as the emitter. This system can be made tunable continuously from 6-11 microns which makes this an eyesafe laser system. In addition, identical SRS cells are used as low noise, narrow band receivers that are sensitive to extremely low levels of scattered laser radiation. Use of this technology is to generate a pair of pulses at different wavelengths for DIAL applications. A description of this system will be provided along with test results.

Prospects of using parametric and SRS oscillators and amplifiers for remote spectroscopy of the atmosphere and image amplification

The possibility of using OPO and two-cascade OPO-SRS converters is considered both for the generation of probing pulses and for the amplification of radiation scattered in the atmosphere. The lidars based on such combined use of OPO and OPO-SRS converters are protected against the background radiation and ensure the probing distance in the IR a few times greater than when the conventional lidars are employed. It is shown that the use of two-cascade parametric and multicascade SRS image amplifiers will make it possible to record the spatial distribution of ultrashort radiation attenuated by a factor of 1013 divided by 1014, having an energy of order 1 mJ, for about 102 image cells.

Tabletop 200 TW 45 fs laser based on optical parametric chirped pulse amplification

200TW peak power at 45 fs pulse duration (910 nm central wavelength) has been achieved experimentally using three optical parametrical amplifiers based on KD*P crystals. Energy conversion efficiency of the final amplifier stage was 25%.

Toward Petawatt Laser Based on Optical Parametrical Amplification: Status Quo and Perspectives

Laser power of more than 100TW (70fs, 10J) has been achieved in experiments on optical parametric amplification of femtosecond pulses in KD*P crystals. Energy conversion efficiency of optical parametric amplifier is 27%.

Front-end system for multi-petawatt laser based on non-generaive optical parametric amplification in KD*P

In a three-cascade optical parametric chirp pulse amplifier based on KD*P crystal the pulse energy was 100mJ at 911nm wavelength. Adding two more parametrical amplifiers (100mm and 300mm diameter) will result in a multipetawatt laser.