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Arrays of both annular and square annular slots in a conducting sheet on a dielectric substrate have been fabricated photolithographically. The structures are shown to behave as bandpass filters in the far infrared, with a resonant wavelength slightly larger than the average circumference or perimeter of the slot. The measured far-infrared transmittance of(More)
A rigorous formulation is used to calculate the transmission properties of a thin, perfectly conducting biperiodic capacitive mesh on a dielectric boundary. The formulation is analogous to the well-known modal method used for inductive meshes, with the modal electric fields replaced by modal currents. Measurements made at submillimeter wavelengths are(More)
The gain and the saturation intensity of optimized cw 337-microm lasers are shown empirically to vary inversely as tube diameter. An expression is then derived for the power of a waveguide laser as a function of geometrical parameters, losses, and coupling. For optimized coupling the power is a strong function of tube diameter with a well defined maximum.(More)
This paper describes the use and advantages of metallic strip gratings on dielectric substrates as output couplers for both optically pumped and discharge-excited submillimeter lasers. Formulas are presented for the calculation of transmittance and loss of such couplers, taking account of loss in the strip grating as well as loss and multiple reflections in(More)
Rapid tuning of a 3-m long glow discharge excited CO(2) laser is achieved by a rotating polygonal mirror scanning the intracavity beam across a diffraction grating. The system can tune through 110 different rotational lines spanning wavelengths from 9.2 to 11.1 microm in 3 ms with typical peak powers of 100-500 W at burst repetition rates up to 360 Hz and(More)
A new library of thermal infrared (TIR) reflectance spectra of rock-forming minerals (silicate, carbonate, sulphate, sulphide, phosphate, oxide minerals etc.) as well as common rocks is being compiled. The focus of the work was to build up a spectral reference dataset for qualitative and quantitative analysis of bi-directional TIR reflectance spectra(More)