Free-Space Terahertz Spectrum Analysis With an Optoelectronic Hybrid System
by A. Theis, M. Kocybik, G. von Freymann and F. Friederich
Abstract: This paper presents a hybrid optoelectronic approach to high-resolution free space spectroscopy. The innovative laser difference stabilization technique is accomplished with optical phase locked loops (OPLL) between at least two optically controlled distributed feedback (DFB) diode lasers and a free running laser, with a precise and stable signal from an active electronic multiplier chain as a reference to lock the beat signal of each laser pair and consequently to phase lock all the lasers. Resolution bandwidth (RBW), primarily a function of the spectral width of the laser beat signal of the demonstration system, was approximately 100 Hz.