The Study Of Terahertz Wave Generation, Detection And Shaping Technology

Terahertz(THz)radition,also known as T-rays,usually refers to the region between the infrared and microwave of electromagnetic spectrum,and is typically characterized in the frequency range of0.1THz to10THz.THz wave has many attractively properties,and thus can provide a great potential applications in many fields,such as civil,military,industry,agriculture,medical security and counter-terrorism, and so on.THz wave has become the hot spots of the study of electromagnetic radiation.In the past few years,rapid progress in ultrafast laser technology provides a reliable and steady souce for the THz generation,which greatly promotes the research in the THz region that is difficult to access before.The paper is organized as follows:First,we describe the method to generate and detect THz wave and construct THz wave generation system by means of the photoconductive antenna technology and THz wave detection system by using free-space electro-optic samping technology.We obtain the calculating formulas of near-filed and far-field of THz wave that generated by photoconductive antenna,and also calculate the intensity and power of THz wave.Second,we employ three-dimensional finite-difference time-domain method to simulate the process of typical THz pulse pass through rectangular aperture.THz pulse shaping effect of the width,thickness and observation position of the rectangular aperture are analyzed. The results show that we can achieve effective shaping and filtering of THz pulse by means of rectangular aperture.When the polarization direction of the incident THz pulse is perpendicular to the long side of the rectangular aperture,it has a good effect on shaping and filtering.While,when the polarization direction of the incident THz pulse is parallel to the long side of the rectangular aperture,it almost has no obvious effect on shaping and filtering.Third,we employ FDTD method to simulate the process of typical THz pulse pass through circular aperture.THz pulse shaping effect of the radius and thickness of the circular aperture are analyzed. Circular aperture has a better effect on shaping and filtering of THz pulse than rectangular aperture.The shaping THz pulse can be applied on the THz imaging,molecular coherent control,submillimeter communication and so on.