BROADBAND TERAHERTZ RADIATION GENERATION AND DETECTION SYSTEM AND METHOD

摘要

The invention relates to a broadband Terahertz (THz) radiation generation and detection System and method. THz radiation is generated by optical rectification of an ultrashort pump pulse of a first wavelength having a duration in the picosecond- or sub-picosecond ränge in a first nonlinear optical crystal. The THz radiation is detected by electro-optic sampling or another appropriate method of a probe beam having a second wavelength in a second nonlinear optical crystal. According to the invention, at least one of the following conditions is fulfilled: a) the first wavelength is different from the second wavelength; b) the material of the first nonlinear optical crystal is different from the material of the second nonlinear optical crystal. This makes it possible to chose for the generation and for the detection process - independent of one another - the combination of wavelengths and nonlinear material and possibly other features of the pump/probe pulses like polarization with the highest efficiency for generation and detection of Terahertz pulses, respectively. In a preferred embodiment, lasers emitting in the infrared ränge are used to generate THz radiation in DAST crystals, and the frequency doubled beam is used to coherently detect the THz radiation in a Standard material like ZnTe. This makes it possible to provide efficient, stable, compact and cost effective THz Systems.