Hybrid Continuous-Wave Demodulating Multipixel Terahertz Imaging Systems

We present an electrooptic (EO) terahertz imaging technique providing a demodulating detector array for phase-sensitive multipixel terahertz detection. The terahertz radiation from a quartz-stabilized microelectronic emitter is mixed with the synchronized laser beat signal of a continuous-wave distributed-feedback diode laser pair. A fast laser current control loop provides stable phase locking between the terahertz emitter and the laser difference frequency, whereby a demodulating near-infrared photonic-mixer-camera is used for depth-resolving EO terahertz imaging. Alternatively, a femtosecond laser is used for the EO read-out.