High performance at new FIR wavelengths from optically pumped CH(2)F(2).

A parametric study to clarify efficiency limiting mechanisms and to maximize the performance of the CH(2)F(2) laser has led to the discovery of five new CO(2) pump lines and ten new FIR laser lines. The wavelengths of the new lines fill a previous gap in the spectrum of strong cw FIR laser lines. With appropriate cavity design, measured conversion efficiencies exceed 30% of the maximum theoretical limit. Optimization of the output coupling for the strongest line at lambda = 184.6 microm has doubled the maximum output power from the identical system using the lambda = 118.8-microum line of CH(3)OH. The exceptionally high conversion efficiency (33%) occurring at the highest-available CO(2) pump power indicates that the limits on scaling to higher output powers have not yet been reached. The results confirm the high-performance capability of the CH(2)F(2) laser, the strongest cw optically pumped FIR laser reported to date.

Hybrid metal mesh-dielectric mirrors for optically pumped far infrared lasers.

A hybrid metal metal-dielectrically coated mirror, highly reflecting in the near ir and partially transmitting in the far ir, for use in optically pumped molecular lasers, is described. Ge and CaF(2) were used for the dielectric films, along with Ni meshes deposited on Si substrates. The dielectric dispersion properties of the CaF(2) thin films were studied in the 2-15-microm range to provide design data. With a four layer dielectric coating and a metal mesh, the specular reflection of the mirror could be maintained greater than 90% over a 2-mum range in the near ir, and by choice of mesh, the transmittance in the 400-600-microm range varied from 0% to greater than 40%.

Far infrared optical properties of selenium and cadmium telluride.

The optical constants of Se and CdTe have been measured in the far ir from 10 cm(-1) to 100 cm(-1) using Fourier transform spectroscopy. An oscillator model has been fit to the available data for both materials over the entire ir range from 10 cm(-1) to 10,000 cm(-1). Several three-phonon absorption peaks have been observed and identified in the absorption spectra of Se. The linear optical properties of these important ir materials have been summarized throughout the ir region.