Design Of Active Terahertz Perfect Absorber Metamaterial And Set-up Of Experimental System

Metamaterial is a kind of artificial structural composites rising gradually recentlywith special characteristics which do not present in the natural material. And it hasbecome a focus in THz wave band for which there are few functional devices.Metamaterial absorbers, a kind of metamaterial, have led to a rapidly growingresearch field in recent years since they were initially researched by Landy et al. Thatthey have a high performance to achieve strong absorption coefficients at specificfrequencies is meaningful for THz-probing and THz-sensing. Currently a lot ofresearches has focus on the structure, resonance frequency and absorption, but most ofthe designs are only modulated by changing their material and composition. Toachieve actively tunable prefect absorber is one of the trends with the development ofnew theory.In this case, we will do researches on theoretical, numerical and experimentalanalysis of a novel design of perfect absorber modulated by infrared light.The main thesis is as follows in short:1. First we will summarize previous experience and propose our perfect absorber.The previous design basically limited to control the absorber with transshipping it. Werealize active control by introducing semiconductor whose characteristic is in controlof the external environment to the design of absorber. For example, we could controlthe amplitude of absorption by variable illumination.2. The characteristics of absorber were presented by its reflection. But there aresome drawbacks such as complication and unwieldiness in the original reflectiveTHz-TDS. In view of this we are going to build a fiber-reflective THz-TDS which ismuch more flexible. In the second part of the thesis we will elaborate how to constructthe kind of experimental system and what we should pay more attention to in theprocess of building. And we will analyze the simulated and experimental result inorder to find the shortcoming of our project and give the suggestions for improvementto direct the next part of the project.