High-power self-controlled volume-discharge-based molecular lasers

Abstract

An investigation is made of the characteristics of the formation of a self-controlled volume discharge for pumping CO 2 lasers, i.e., self-sustained volume discharge (SSVD), which involves the preliminary filling of a discharge gap by an electron flux from an auxiliary discharge plasma. It is determined that this method is suitable for large interelectrode gaps, that distortion of the electric field in the gap by the space charge of the electron flux plays an important role in the formation of the discharge, that the electrodes could be profiled dynamically during propagation of an electron flux through the discharge gap, and a SSVD could form in systems with a strongly inhomogeneous field. High-power SSVD-based CO 2 laser systems are created and investigated. Another type of self-controlled volume discharge without preionization, i.e., a selfinitiated volume discharge (SIVD), in nonchain HF lasers with SF 6 -C 2 H 6 mixtures is also investigated. It is established that, after the primary local electrical breakdown of the discharge gap, the SIVD spreads along the gap in directions perpendicular to that of the electric field by means of the successive formation of overlapping diffuse channels under a discharge voltage close to its quasi-steady-state value. As new channels appear, the current that flows through the channels formed earlier decreases. The volume occupied by the SIVD increases when the energy deposited in the plasma increases, and, when the discharge volume is confined by a dielectric surface, the discharge voltage increases simultaneously when the current increases. The possible mechanisms that explain the observed phenomena, namely the dissociation and electron attachment of SF 6 molecules, are examined. A simple analytical model is developed that makes it possible to describe these mechanisms at a qualitative level. High-power SIVD-based HF(DF) lasers are developed and tested.

High energy HF (DF) lasers

“…This igure re lects the data we obtained using setups with different volumes of active medium. This allows us to predict the possibility of further increases to the output energy of non-chain HF (DF) lasers through the creation of setups that operate at energy deposi tions above a few tens of kJ using the methods we developed during that very productive period of time [33,34].…”

Studies on high energy pulsed CO 2 laser

“…The electrode structures are all shown in Fig.2 where the lateral UV sparks are omitted. Stable pulsed discharge in much wider discharge gap could be realized by the scheme of UV preionization beneath mesh electrode, [9] for the distance between the UV radiation source and the main discharge zone is much shorter than the lateral preionization scheme. Two systems with 70 mm gap were established.…”

Environmentally friendly HF (DF) lasers

“…This figure reflects the data we obtained under the guidance of Academician A M Prokhorov using setups with different volumes of active medium. This allows us to predict the possibility of further increases to the output energy of non-chain HF (DF) lasers through the creation of setups that operate at energy depositions above a few tens of kJ using the methods we developed during that very productive period of time [30][31][32]. and S I Zienko.…”