Applied Physics Letters · 1997 · 47 citations · 9 references
Thz PhotonicsSpectroscopic ApplicationsOptical MaterialsEngineeringLaser ScienceTunable SourceThz RadiationLow-temperature-grown GaasTerahertz PhotonicsOptical PropertiesOptical SpectroscopyFrequency LockingPhotonicsTerahertz SpectroscopyTerahertz ScienceSpectroscopyApplied PhysicsTerahertz TechniqueTunable LasersNoise FloorOptoelectronics
A compact, narrow-linewidth, tunable source of THz radiation has been developed for spectroscopy and other high-resolution applications. Distributed-Bragg-reflector (DBR) diode lasers at 850 nm are used to pump a low-temperature-grown GaAs photomixer. Resonant optical feedback is employed to stabilize the center frequencies and narrow the linewidths of the DBR lasers. The heterodyne linewidth full-width at half-maximum of two optically locked DBR lasers is 50 kHz on the 20 ms time scale and 2 MHz over 10 s; free-running DBR lasers have linewidths of 40 and 90 MHz on such time scales. This instrument has been used to obtain rotational spectra of acetonitrile (CH3CN) at 313 GHz. Detection limits of 1×10−4Hz1/2 (noise/total power) have been achieved, with the noise floor dominated by the detector’s noise equivalent power.
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Terahertz photomixing with diode lasers in low-temperature-grown GaAs
K. A. McIntosh, E. R. Brown, K. B. Nichols et al. · Applied Physics Letters · 1995 · 316 citations