Energy Conversion Efficiency Calculation Model For Direct-bonding Planar-waveguide THz Emitters Based On Optical Rectification Effects In GaAs

the terahertz (THz) frequency range that covers from 0.1 to 10 THz has become a frontier for research in physics, chemistry, biology, materials science, and medicine. Recently, significant advances in THz science and technology have opened up a wide range of potential research opportunities. Applications including label-free DNA genetic analysis, cellular-level imaging, chemical/biological sensing,explosives detection, tomographic imaging, and nondestructive testing have thrust THz research from relative obscurity to new heights.It’s possible to using the low cost fiber laser whose centre wavelength is 1550nm to replace the expensive Ti-Sapphire laser as the development of technology. The subject is also part of the National Natural Science Foundation project "New hybrid waveguide device design and fabrication for THz emitters" (Grant No.: 60578022)In using nonlinear crystal to generate THz under optical rectification process, phase match condition can be promoted through well-designed waveguide structure.An asymmetric waveguide structure is proposed in this article,GaAs is the core layer of the waveguide,air is the cladding and Silicon as the substrate.The best matched THz frequence is changed with the thickness of the waveguide. 1.5THz and 1THz can be well matched when the waveguide thickness is 90 um and 140um.The waveguide structure can be made by direct bonding of GaAs and silicon.THz electric field component, spectrum and THz conversion efficiency was calculated by numerical simulation using the above waveguide, THz conversion efficiency was 1.5*10-3 ,it’s an order of magnitude higher than the best reported 5*10-4.