Highly sensitive coherent detection of terahertz waves at room temperature using a parametric process

Abstract

We report the experimental results of coherent detection of narrow-linewidth nanosecond terahertz radiation at room temperature using frequency conversion in a nonlinear MgO:LiNbO3 crystal. Mixing the terahertz radiation with a near-infrared intense pump pulse results in the excitation and amplification of the difference-frequency component, which is detected with an InGaAs-based photodiode. We demonstrate this method in a fast and very sensitive terahertz wave detector. The detector is capable of capturing the temporal profile of terahertz pulses with nanosecond resolution, and is at least one order more sensitive than a typical liquid-He-cooled Si bolometer for detecting nanosecond pulsed terahertz wave beams.

Monochromatic, wide tunable terahertz-wave generation and detection system working at room temperature

“…The detection part consisted of the equilateral trapezoidal input coupling crystal and a 130 mm length amplifying crystal. [7] All of the TPO cavity, the crystals in the TPO, the crystals for detection and the optical detector are fixed. Frequency tuning was realized by employing an angle-tuning mirror (controlled by a Galvano-optical beam scanner) and a telescope in the pump beam.…”

“…Mixing of THz-wave radiation in MgO:LiNbO 3 with a single longitudinal-mode Q-switch YAG pump laser generates a difference frequency component, using this method, we have demonstrated a fast-response and very sensitive THz-wave detection system [7]. In this letter we extend our THz detection capability to realize an automatic, wide frequency range THz-wave detection at room temperature.…”

“…Recently, several groups observed that a difference frequency was generated when weak THz was mixed with strong near-IR waves using nonlinear crystals like GaSe, GaAS, PPLN, bulk-LiNbO 3 and so on [6][7][8]. Their results demonstrate frequency up-conversion as an effective method to realize a high sensitivity THz-wave detection system working at room temperature.…”

Sensitive terahertz-wave detector using a quasi-phase-matched LiNbO3at room temperature

“…Nonlinear optical detection using various bulk crystals such as LiNbO 3 , [4,5] GaSe, [6] GaP, [7] ZnGeP 2 , [8] GaAs, [9] and 4-dimethylamino-N'-methyl-4'-stilbazolium tosylate (DAST), [10] has been promoted as a promising technique for sensitive THz detectors. Response to THz energies of less than a femtojoule has been achieved.…”

A Method of Calibration of Terahertz Wave Brightness Under Nonlinear-Optical Detection

“…The most widely used one among these methods is the method of electro-optic sampling, which operates under femtosecond pulsed pumping [4,5]. Quasi-continuous wave THz detection was also demonstrated recently [8,9]. This detection mode is closer to the goals of compact generation/detection devices.…”