Condensation of the emission spectrum of a wide-band laser in the case of intracavity emission scattering by an aerosol

It is found that inserting aerosol in a cavity of a multimode (wide-band) Co:MgF₂ laser can strongly affect its emission spectrum, provided the typical size of aerosol particles is comparable to the laser wavelength (~2 μm). In the presence of aerosol, intensity spikes are formed in the spectrum at the initial lasing stage, which develop in time. At moments of time ~100 μs, condensation of the spectrum was observed, which manifested itself as a sharp (more than two orders of magnitude) narrowing of the laser emission spectrum down to the value determined by the spectral resolution of a spectrograph (not better than 0.04 cm^–1), with an insignificant decrease in the output energy.