Influence of laser-pulse shape and surface recombination on the photon generation rate in experiments on the dynamical casimir effect

We study the influence of laser-pulse shape and surface recombination on the photon generation rate in the so-called MIR experiment on the dynamical Casimir effect. Numerical calculations show that the surface recombination can be neglected at low (helium) temperatures and its influence on the photon recombination rate is rather small at higher (nitrogen) temperatures. It appears that long (tens of picoseconds) laser pulses could be preferable for semiconductors with very small (less than 10 ps) bulk recombination times. Moreover, for a given energy of laser pulses (exceeding some critical value), it is possible to find a pulse duration such that the photon generation rate becomes almost independent of the recombination time in a rather wide range of values (about 25 ps). These results can facilitate the performance of the experiment.