Contents 1. INTRODUCTION
The Tera-Hertz wave refers to the electromagnetic wave with the frequency from 0.1 THz to 10 THz. In recent years, a large number of studies have been focused on the applications of the Tera-Hertz sources based on its unique characteristics between microwaves and infrared lights, which including the plastic inspection [1], spectroscopic imaging [2], and material research [3]. The Tera-Hertz spectrometer is one of the essential equipments in the above studies. One of the Tera-Hertz wave generation methods is based on two beat laser lights when their wavelengths are close enough. In order to obtain a Tera-Hertz spectrum, at least one of the two beat lasers must be a wavelength tunable laser. The tunable laser is a sophisticated device, which is widely used in the fields of the optical communications, absorption spectroscopy and optical coherence measurements. For the current commercial available Tera-Hertz system, its laser tuning is realized by changing the operation temperature tuned. However, temperature tuning requires a self-contained temperature control device, which causes a low tuning speed and the tuning accuracy is also difficult to be guaranteed. In this study, we proposed a laser beat system by current tuning, not by temperature, and applied in a Tera-Hertz spectrometer. The continuous Tera-Hertz spectrum can be generated by using two sets of feedback loops to control the current of twin tunable laser. Relatively, the current tuning is quicker and more accurate.
