Victor I. Kuprenyuk

Feasible configurations of a repetitively pulsed TEA CO2 laser with small angular divergence and 1- kJ pulse energy

The results are presented of expert evaluations aimed at developing the optimal concept of creation of a compact TEA CO2 laser with a self-sustained discharge capable of generating the repetitive bursts of ten radiation pulses with 1 kJ-energy in each and the pulse repetition rate of 30 Hz. Particular emphasis is placed on the problems of achieving as small angular divergence and beam wandering as possible.

On a Possibility of Laser Beam Control in LOTV Mission by Means of Nonlinear and Coherent Optics Techniques

In the context of LOTV Mission (Laser Orbital Transfer Vehicle) the analysis of laser beam delivery efficiency has been carried out for power beaming with a 200‐kW‐solid‐state laser from an aircraft to a space “tugboat” having a beam receiving collector of 10‐meter‐size. Application of nonlinear‐optics and adaptive optics techniques of laser beam control for correction of optical distortions in the propagation path caused by vibration and thermal deformation of optical elements as well as by atmospheric turbulence is discussed. Possible architecture of laser beam transport systems including a laser beacon on the receiver, a repetitively pulsed solid‐state laser in MOPA‐PCM configuration and a beam director telescope of 1‐meter size is considered. The results of computer simulation of a MOPA‐PCM system as well as the system as a whole are presented. The requirements to optical elements of the system are discussed.

CO2 lasers and phase conjugation

Abstract not available.

CW chemical HF/DF laser operating in the Q-switch mode

The numerical end experimental study of the energy and temporal characteristics of the output radiation of the CW medium-scale chemical HF/DF-laser with mechanical modulation of the optical resonator quality by the mirror rotation with frequency up to 1 kHz is carried out. In experiment, a peak power of the laser radiation pulses has exceeded the radiation power in CW mode of the HF-laser operation not less than in four times. The average power in repetitively pulsed mode is lower than one in CW mode, but it grows with increase of the modulation frequency. Time of the complete recovery of a small signal gain of the active medium, which is about 6 - 7 &mgr;s, is determined. Two numerical models are developed, which describe the dynamics of the laser oscillation in a mode of the resonator quality modulation for both HF- and DF-laser, some features of their operation are analyzed using these models.

Computer Simulation of a Solid‐State Laser System for Propulsion of a Space “Tugboat” from LEO to GEO

Development of Laser Orbital Transfer Vehicles (LOTV) driven by an aircraft‐based laser requires correction for laser beam distortion caused by the aircraft vibration, thermal deformation of laser optics, turbulence and nonlinear effects in upper layers of the atmosphere, etc. We have analyzed a possibility of combined use of an adaptive optics system (AOS) and phase conjugate mirrors (PCM) for the beam clean up and correction for turbulent distortion using a beacon laser at the “tugboat”. The analysis is performed for a repetitively pulsed 200 kW Yb:YAG diode‐pumped solid‐state laser with a 1 meter class beam‐director. The results of computer simulation of the system performance for different distances from 300 to 36000 km are presented.

Experimental verification of a bright-speckle algorithm of compensation for turbulent wandering of a repetitively pulsed CO2 laser beam

A novel algorithm of compensation for repetitively-pulsed laser beam wandering at propagation paths, caused by the atmospheric turbulence and mirror vibrations has been proposed and verified in experiments with a TE-CO2 laser. The algorithm is based on the precise temporal control of triggering each of the TE-laser pulses at the moments when the auxiliary probe cw-laser beam modified by a modal-type adaptive optics system and having exactly the same wavefront profile, as the pulsed radiation, hits the remote object (retroreflector in the pre-set point at the path exit) by its brightest speckle.

Phase conjugation of cw chemical laser radiation by four-wave mixing in an absorbing liquid

Solution of the problem of creating efficient phase conjugate mirrors (PCM) for radiation of cw chemical lasers (CWCL) will make it possible to extend the scope for applications of high- power low-divergence radiation in the 2 - 3 micrometer spectral region which currently draws active interest. Both four-wave mixing (FWM) and stimulated Brillouin scattering using some threshold decreasing schemes can be employed as a technique for implementation of an efficient PCM for the lasers of this type. In this paper, we present the results of the phase conjugation implemented for the CWCL radiation using the FWM in a liquid with thermal nonlinearity. This mechanism has been studied in detail as applied to the cw carbon-dioxide lasers, for which it so far remains to be the only technique for creating efficient PCMs. Threshold-free PCMs based on the FWM process in absorbing liquids are capable of providing nearly 100% reflectivities and may find application for dynamic aberration correction in the optical paths, coherent addition of laser radiation channels, and for laser beam direction control.

Phase conjugation for pulse-repetition CO2 laser with millisecond pulse duration

The results of the theoretical and experimental study of four-wave mixing of repetitively pulsed CO2 laser radiation is discussed. The PC-cell with the water-cooled mirror is used. Toluene and Xe-SF6 gas mixture are used as nonlinear media.