Extension of the Range of Microwave Spectroscopy up to 1.3 THz

A Terahertz Photomixing Spectrometer: Application to SO2Self Broadening

“…Photomixand the BWOs have enough power for photoacoustic (23) ing, on the other hand, is frequency independent below the or, perhaps, pyroelectric detection. The resolution, precision, inverse lifetime of the material and RC time constants of and accuracy of all these other THz sources currently exceed the device (10,11) and shows great promise for generation those of the photomixer described here, whose linewidth is of far-infrared radiation in ultrafast photodetectors.…”

“…Harmonic generation from microtion sources have been developed for high-resolution molecwave klystrons, Gunn oscillators, and other solid state ular spectroscopy using difference-frequency mixing of cw devices also access portions of this range as well as fundadye (1-3), Ti:sapphire (4), and diode (5) lasers in various mental radiation from carcinotrons (22) and other backwardbulk nonlinear optical crystals. Extension to the far-infrared wave oscillators (BWOs) (23,24). Most of these microwaveby mixing cw CO 2 lasers in GaAs has been demonstrated type systems use fast Schottky diodes as harmonic generators (6), but with the reduction of conversion efficiency by the or mixers for phase locking.…”

A Quasi-Optical Multiplier for Terahertz Spectroscopy

“…Previous tests [11] of BWO driven tripler/quadrupler at 300 GHz fundamental frequency showed good input coupling (pumped Diode current > 1 mA @ 10 /iA Bias) by use of an overmoded single ridge input waveguide (2.4 mm x 1.2 mm) combined with an E-H plane tuner. Because of the rapid decrease of the multiplying efficiency at higher harmonics, it seems advantageous in most cases to increase the fundamental frequency.…”

Accurate broadband rotational BWO-based spectroscopy

“…One of the harmonics of this synthesizer, produced by a multipliermixer based on a Schottky diode, served as a reference signal in submillimeter frequency synthesizers (see, for example [6]). The construction of the most widely used quasi-optical multipliermixer operating without tuning in the 200-1100 GHz range is described in [7][8][9]. BWO frequency control was realized through a small additional voltage produced by a phase detector and video amplifier and applied to the 50-100 X resistor connected in series with the main high-voltage BWO supply.…”