High-power pulse and pulse-periodic nonchain HF (DF) lasers

Abstract

This paper reports on the physics of a self-sustained volume discharge without preionization, self-initiated volume discharge (SIVD), in working mixtures of nonchain HF(DF) lasers. Dynamics of SIVD in discharge gaps of different geometry is thoroughly described. The mechanisms of restricting current density in a diffuse channel in electric discharges in SF6 and SF6 based mixtures determining the possibility of the existence of SIVD were suggested and analyzed using simple models. It is shown that the most probable mechanisms are the electron impact dissociation of SF6 and other mixture components, electron-ion recombination and electron attachment to vibrationally excited SF6 molecules. Starting from a comparison analysis of the rate coefficients of these processes, it was found that the electron-ion recombination is capable of compensating for electron detachment from negative ions by electron impact. It is established that SIVD can be observed not only in SF6, but in other strongly electronegative gases, e. g., in C3F8 and C3HC13. Analysis is given of the factors determining uniformity of active medium in nonchain HF(DF) lasers. Some special features of operating nonchain HF(DF) lasers with small, 2÷6cm, apertures are carefully examined and the results of measuring the nonchain HF(DF) laser divergence are presented. Consideration is given to the problem increasing the aperture and discharge volume of nonchain HF(DF) lasers and, based from the experimental results, the possibility is shown of increasing their energy to a level of lkJ and above.

Discharge initiated high power repetitively pulsed HF/DF laser

“…With different process of chemical reaction to the chain HF/DF laser, small size non-chain HF/DF laser can be operated on high pulse repetition-rate with high peak power. It has possible applications in atmospheric pollution detection, medicine, and processing of materials [1,2] . With discharge initiated repetitively pulsed HF/DF laser, obtained stable glow discharge is the precondition for electrical energy transfer and laser energy extract efficiency.…”

Discharge pumped non-chain repetitively pulsed HF laser

“…For different process of chemical reaction comparing with the chain HF laser, it can be operated on high pulse repetition-rate with high peak power [1,2] . With above properties, the non-chain HF laser has possible applications for various science and technology purposes, such as detection of atmospheric pollution, medicine, and processing of materials [3,4] .…”

Pulse energy sustainability of a burst mode closed-cycle pulsed HF chemical laser

“…On the one hand, persistent endeavor has been made to scale up the output pulse energy. In 2002, exploiting the self-initiated volume discharge technology, Apollonov reported a non-chain HF laser system with over 400 J output in one single pulse [11]. The feasibility of increasing the energy to 1 kJ was also demonstrated [12].…”