Numerical investigations of the dependences of the output characteristics of the ion strontium vapor laser on the pressure and temperature of the active medium were carried out. Based on the results of calculations, a range of conditions for the excitation of the active medium was found for the realization of the multiwave lasing regime on visible and infrared transitions of the strontium ion (λ=430.5; 416.2; 1091 and 1033 nm SrII). A number of patterns were revealed that are inherent in the active medium of a strontium vapor laser, and the physical mechanisms that determine them were established. The investigations results provide a possibility to choose the conditions for optimal excitation of multiwave strontium vapor lasers, as well as to control the relative contribution of various spectral components to the output radiation.
Keywords: multiwave radiation, recombination pumping, self-termination transition, strontium vapor laser, numerical modeling
Possible methods of high-speed control of the output characteristics of recombination He-Sr and He-Ca lasers using mathematical models are analyzed. The capability is demonstrated of wide-range control of laser output characteristics with the help of two methods – by varying the amplitude of the additional current pulse imposed on early afterglow of the pulse-periodic discharge and by varying the moment of this pulse imposing. The dependences of the laser output characteristics on the parameters of the additional current pulses are numerically calculated. The mechanism of their influence on the population of laser levels is established. The results obtained make it possible to purposefully form control current pulses for the recombination metal vapor lasers.
Keywords: recombination metal vapor laser, He-Sr-laser, He-Ca laser, gas-discharge plasma, fast controlling, mathematical modeling
An analysis of the mechanisms limiting the growth of the output characteristics of ion recombination He-Ca lasers with an increase in the active medium volume and frequency of pulse repetition is carried out. It was established that by a growing laser tube diameter and a growing frequency of pulse repetition the average power of He-Ca lasers saturates and then decreases due to the formation of radial non-uniformity of the active medium as a result of its overheating on the axis and of the radial cataphoresis, as well as because of the raise of the electron temperature level in early afterglow, conditioned by the grow of gas temperature. It is pointed out that as possible ways of increasing the output characteristics can be used the blackening of the laser tube surface, the use of an independent input of calcium vapours, the use of a forced cooling, while the application of a tube with rectangular cross-section will allow to maximally increasing the energy characteristics. Based on numerical computations it is shown that the attainable maximum of running power of He-Ca lasers amounts to: ~ 4.4 W/m for self-heating active elements from BeO-ceramics and ~ 5.2 W/m – on blackening their surface; ~ 5.3 W/m for an independent calcium vapours input and ~ 6.2 W/m – for its combination with blackening; ~ 9.5 W/m for an intensive forced cooling of active elements with cylindrical geometry; ~ 16 W/m – with active elements of rectangular cross-section at a ratio of wall sizes 1:3.
Keywords: metal vapor laser, the ion recombination He-Ca laser, pulse-periodic discharge, gas-discharge plasma, self-heating regime, mathematical modeling