Title :
Tunable cw THz source with high-precision frequency control
Author :
Deninger, Anselm J. ; Göbel, Thorsten ; Schönherr, Daniel ; Roggenbuck, Axel ; Lison, Frank ; Meissner, Peter
Author_Institution :
TOPTICA Photonics AG, Grafelfing
Abstract :
We realized a tunable continuous-wave terahertz (cw THz) source with MHz frequency resolution. The system is based on optical heterodyning of two near-infrared Distributed Feedback (DFB) diode lasers, each laser being stabilized by electronic feedback from a low-finesse quadrature interferometer. The control loop permits precisely linear laser frequency scans over >1200 GHz, and a beat signal linewidth of 1 MHz @ 80 ms time scale. Using GaAs photomixers and log-periodic antennae, we achieve an SNR of the THz power of > 70 dB at 100 GHz and 100 ms integration time, and still ~ 30 dB @ 1 THz. As an example for high-resolution THz spectroscopy, we characterize the transmission properties of a sub-wavelength metal grating.
Keywords :
distributed feedback lasers; frequency control; gallium arsenide; semiconductor lasers; submillimetre wave antennas; submillimetre wave mixers; submillimetre wave spectroscopy; terahertz waves; GaAs; MHz frequency resolution; electronic feedback; frequency 1 THz; frequency 100 GHz; high-precision frequency control; high-resolution THz spectroscopy; log-periodic antennae; low-finesse quadrature interferometer; near-infrared distributed feedback diode lasers; optical heterodyning; photomixers; sub-wavelength metal grating; transmission properties; tunable continuous-wave terahertz source; Diode lasers; Distributed feedback devices; Frequency control; Laser feedback; Laser stability; Optical feedback; Optical interferometry; Optical mixing; Signal resolution; Tunable circuits and devices;
Conference_Titel :
Infrared, Millimeter and Terahertz Waves, 2008. IRMMW-THz 2008. 33rd International Conference on
Conference_Location :
Pasadena, CA
Print_ISBN :
978-1-4244-2119-0
Electronic_ISBN :
978-1-4244-2120-6
DOI :
10.1109/ICIMW.2008.4665483
