Vladimir V. Stepanov

Model Test of the Aerospace Laser Propulsion Engine

One of the main results of the experimental and theoretical investigations made under the ISTC Project ♯ 1801 is the original design of Aerospace Laser Propulsion Engine (ASLPE) developed. The designed characteristics of the ASLPE flight model are experimentally approved, including the test experiments with a solid propellant. The obtained momentum coupling coefficient is rather high and comparable one with respect to the coefficient obtained by other researchers. Moreover, it is experimentally demonstrated that the thrust characteristics of the ASLPE flight model does not depend on angular aberrations of the beam coming onto the beam concentrator of the model with the incident angle of 0.01 radian. The experiments also demonstrated that successful launching of the vehicle with the ASLPE under the laser characteristics is possible also if the vehicle mass will be decreased and the thermal blooming effect will be eliminated.

Phase conjugation in a high-power E-beam-sustained CO2 laser

The experimental demonstration of phase conjugation technique as applied to aberration correction in a high-power gas-flow CO2 laser is reported. A four-wave mixing in 34SF6 was used to obtain high efficient phase conjugation of repetition rate electron- beam-sustained CO2 laser radiation. For the first time, the nearly diffraction-limited performance of the double-pass CO2 amplifier with the phase-conjugate mirror for the output energy of about 1.2 KJ and average power of 40 KW is demonstrated.

Self-phase conjugation of middle-infrared radiation by four-wave mixing in active medium of CO2-laser with feedback loop

The ring cavity oscillation at the four-wave mixing in the carbon-dioxide-laser medium with feedback loop was studied. The cavity output energy about 5 J at the master oscillator energy of 0.5 J was observed, the phase conjugation fidelity ranged from 0.3 to 0.8.

Laser Beam Control System To Compensate The Turbulent Distortions Of Laser Beam At Introducing A Lead Angle

The peculiarities of laser radiation delivery to a space vehicle in the concept LOTV which are concerned to the introduction of a lead angle is considered. It is shown that the use of direct phase conjugation of radiation of a laser beacon beam placed on a space vehicle does not provide a required degree compensation of the radiation phase distortions caused by the turbulent atmosphere. Two‐circuit adaptive laser system for high — power radiation delivery is offered in this case. In the system the processes of registration of the information about atmospheric distortions and formation of radiation are functionally partitioned. A key element of the system is a hologram — corrector being phase analogue of distortion occurring in the laser beam path between the system and lead point.

Simulation of laser propulsion at space conditions

In the paper, the problems of laser propulsion for space application is considered. To simulate the laser propulsion creation, the computer codes are developed. These codes allow us to simulate both gas-dynamics of the propulsion creation and processes of laser pulse interaction with propellants.

Experimental study on phase conjugation correction of distortions imposed by telescope elements

The paper presents experimental results on large scale carbon-dioxide-laser beam direction, using the telescope with nonlinear-optical dynamic compensation for distortions. Variants, using phase conjugation mirrors on base of SF6-cell and of intracavity four-wave mixing, are discussed and compared.

Four-wave mixing of radiation in the gain medium of e-beam-sustained CO2 laser

The conventional FWM phase conjugation technique and the intracavity one have been studied experimentally in a gain medium of a pulsed e-beam sustained CO2 laser. The total reflectivity of 45% for the phase-conjugate beam energy of 0.3 J is reported. The periodic temporal modulation of the laser output and of the phase-conjugate beam intensity for intracavity FWM arrangement has been observed. Two types of density gratings in the medium (temperature and acoustic ones) are used to explain experimental results.