Two-dimensional Electro-optic Sampling Research Articles

Ultrabroadband and Low-Dispersion Multiple-Joint Transmission-Line for Terahertz Region

A multiple-joint transmission line based on the principle of the periscope was developed to realize the flexible guidance of terahertz (THz) waves. The transmission line has a slightly larger diameter than the standard plastic hollow-pipe waveguide, sufficient stability, low transmission loss, ultrabroadband spectrum, and low dispersion. The transmission line is evaluated using a THz time-domain spectrometer consisting of reflective two-dimensional electro-optic sampling with a high-speed complementary metal-oxide semiconductor camera.

Two-dimensional electro-optic sampling of terahertz radiation using high-speed complementary metal-oxide semiconductor camera combined with arrayed polarizer

We developed a terahertz imaging system based on two-dimensional electro-optic (EO) sampling using a high speed complementary metal-oxide semiconductor (CMOS) camera and an arrayed polarizer matched to the camera. By operating the CMOS camera in a normalized differential mode on a single-shot basis, two-dimensional EO sampling is demonstrated.

Deformation corrected real-time terahertz imaging

The authors have developed a method of real-time terahertz imaging in which image deformation due to nonuniformity of residual birefringence in the electro-optic (EO) sampling crystal is corrected. Real-time terahertz imaging using intense terahertz pulses and two-dimensional EO sampling can suffer from birefringence nonuniformity of the EO crystal since the birefringence is explicitly used for the linear detection of the terahertz field. In the proposed method, the distribution of the residual birefringence of the EO crystal is measured and used for image correction. Deformation-free images of the spatial profile of a focused terahertz pulse were obtained.

Terahertz wideband spectroscopic imaging based on two-dimensional electro-optic sampling technique

We extended the bandwidth of a terahertz (THz) spectroscopic imaging system based on two-dimensional electro-optic sampling. By using an optical-rectification emitter, formed by a ZnTe crystal, a high-frequency component of more than 2.0THz was detected. A calibration-free procedure with polarity inversion of the THz beam ensures us precise spectroscopy: the polarity was inverted by rotating the emitter crystal. The spatial patterns of the chemicals were extracted from the THz multispectral images in the extended spectral region.

Calibration free terahertz imaging based on 2D electro-optic sampling technique

A two-dimensional electro-optic sampling technique with polarity modulation for THz imaging is proposed and demonstrated. The polarity modulation greatly improves the signal linearity to the THz field. Combining this technique with software lock-in detection, it is found that the modulation efficiency is also improved compared to conventional optical chopping.