Preparation of room temperature terahertz detector with lithium tantalate crystal and thin film

Jun Wang,Jun Gou,Weizhi Li

doi:10.1063/1.4865097

Abstract

Research on room temperature terahertz (THz) detector is essential for promoting the application of THz science and technology. Both lithium tantalate crystal (LiTaO3) and lithium tantalate thin film were used to fabricate the THz detector in this paper. Polishing process were used to reduce the thickness of LiTaO3 crystal slice by chemical mechanical polishing techniques and an improved sol-gel process was used to obtain high concentration LiTaO3 precursor solution to fabricate LiTaO3 thin film. Three dimension models of two THz detectors were set up and the temperature increasing map of two devices were simulated using finite element method. The lowest noise equivalent power value for terahertz detector using pyroelectric material reaches 6.8 × 10−9 W at 30 Hz operating frequency, which is suitable for THz imaging application.

Highlights

INTRODUCTIONThe terahertz (THz) region of electromagnetic spectrum is often regarded as the final unexplored area of spectrum and presents a challenge for both electronic and photonic technologies.[1,2] Great promotions of THz research have been obtained in the last ten years including high-power THz wave generation, THz time domain spectroscopy, THz imaging and so on.[3,4,5] THz detectors are playing a key role in wide range of applications such as material identification, imaging, tomography, secured communication, medical detection.[6,7,8,9,10] It’s necessary to develop terahertz detectors with high sensitivity, low coat, room temperature operating, and low complex characteristics
Room temperature terahertz detectors basing on pyroelectric material was reported in this paper
The LiTaO3 crystal slice was polished to 40 micron thickness by chemical mechanical polishing techniques

Summary

INTRODUCTION

The terahertz (THz) region of electromagnetic spectrum is often regarded as the final unexplored area of spectrum and presents a challenge for both electronic and photonic technologies.[1,2] Great promotions of THz research have been obtained in the last ten years including high-power THz wave generation, THz time domain spectroscopy, THz imaging and so on.[3,4,5] THz detectors are playing a key role in wide range of applications such as material identification, imaging, tomography, secured communication, medical detection.[6,7,8,9,10] It’s necessary to develop terahertz detectors with high sensitivity, low coat, room temperature operating, and low complex characteristics. For THz imaging application, room temperature direct THz radiation detection detector for active imaging applications is preferred. The pyroelectric material, especially lithium tantalite (LiTaO3), has been successfully used in infrared region detection,[12,13] and shows great potentials in the direct detection detectors for active imaging applications. Terahertz detectors with both lithium tantalite crystal and thin film are designed, simulated, and fabricated in this paper to obtain high sensitivity device with low cost, real-time, small bulk, room temperature operating performances

PYROELECTRIC MATERIALS PREPARATION

DEVICE STRUCTURE DESIGN

RESULTS AND DISCUSSION

CONCLUSION