Terahertz real time focal plane imaging

In this presentation, some technologies are proposed to improve the performances of the real time focal plane imaging system. Firstly, the quasi near field technology is proposed to effectively improve the resolution. The object is located as close as to the detection crystal, usually the distance between the object and detection crystal is 100μm. Thus the evanescent wave of the object can be detected and hence the resolution can be improved. The balanced detection method has also been adopted to improve the signal noise ratio (SNR). The balanced detection method has been widely used in TDS to improve the SNR, here two CCDs have been used and the probe beam has been separated into two beams. The substraction of two images can present better SNR, the improvement of 4 to 10 times have been achieved. The polarization information about the object is also quite important. An approach is proposed to get the polarization information. In this method, the polarization of the probe beam has been rotated to achieved the electric field distribution on the vertical direction.