Title :
Continuous-Wave THz Homodyne Spectroscopy and Imaging System With Electro-Optical Phase Modulation for High Dynamic Range
Author :
Kim, Jae-young ; Ho-Jin Song ; Ajito, K. ; Yaita, Makoto ; Kukutsu, Naoya
Author_Institution :
NTT Microsyst. Integration Labs., NTT Corp., Atsugi, Japan
Abstract :
We present a terahertz (THz) continuous-wave coherent homodyne spectroscopy and imaging system based on THz phase control using electrooptic (EO) phase modulation for fast measurement without mechanical delay movement. After describing the degradation effects of detection signal by the optical laser noise and parasitic amplitude modulation, we propose the push-pull EO phase modulation with optical delay control for dynamic range enhancement. Using wideband unitraveling-carrier photodiode and InGaAs photoconductive antenna, spectroscopy up to a 1.5-THz frequency range and imaging are demonstrated.
Keywords :
III-V semiconductors; amplitude modulation; antennas; electro-optical modulation; gallium arsenide; homodyne detection; indium compounds; laser noise; optical control; phase control; phase modulation; photodiodes; terahertz spectroscopy; terahertz wave imaging; InGaAs; THz phase control; continuous-wave THz imaging system; degradation effects; dynamic range enhancement; electro-optical phase modulation; frequency 1.5 THz; optical delay control; optical laser noise; parasitic amplitude modulation; photoconductive antenna; push-pull EO phase modulation; signal detection; terahertz continuous-wave coherent homodyne spectroscopy; wideband unitraveling-carrier photodiode; Electrooptic modulators; Laser noise; Optical imaging; Optical mixing; Optical noise; Phase modulation; Continuous-wave; electrooptic phase modulation; homodyne detection; terahertz (THz);
Journal_Title :
Terahertz Science and Technology, IEEE Transactions on
DOI :
10.1109/TTHZ.2012.2228896
