Multipass Cavity Research Articles

Multipass resonators for annular gain lasers

The need to obtain a coherent output beam may impose severe constraints on the design of lasers with annular amplifying regions. One solution to the mode control problem involves resonant cavities in which the optical fields make more than one pass through the amplifying medium before returning to their starting point on the cavity mirror. Such multipass cavities and the resulting phase-compensated beam modes are considered in detail.

Simplified theory of a multipass cw gasdynamic laser cavity

The paper concerns a simplified analysis of the problem of the power extraction from the multipass cavity of the cw gasdynamic laser. Analytical formulas for the laser output and the resonator efficiency are given relating them to the cavity geometric features, cavity losses, number of the cavity passes, and gain and population inversion of a flowing optically activated medium. The analysis is oriented toward application of the obtained results for a rapid estimation of the power characteristics of a CO2 (or N2O)/N2/(additives) cw gasdynamic lasers. The interaction between gain and radiation field is treated in terms of the rate-equation formalism.

A simple multipass cavity accessory for infrared spectroscopic measurements on thin polymer films

A simple multipass 'cavity' accessory has been designed and built for the enhancement of absorption intensity and elimination of optical interference effects in the infrared spectroscopic examination and analysis of thin polymer films. Use of the accessory in conjunction with a Wilks MIRAN non-dispersive infrared analyser is illustrated by application to the spectroscopic analysis of propylene/ethylene copolymer films.