Research On The Integration Detection Method Of Optical And Radio Frequency Electromagnetic Waves Based On Functioned Metamaterials

So far, how to acquire an effective method of integration detection optical and radio frequency electromagnetic waves has become a hot topic in the field of high performance radiation detection covering a relatively wide wavelength range. A key approach for realizing the integration detection of optical and radio electromagnetic signals, is to find an unified physical architecture sensing both types of electromagnetic radiation mentioned above, so as to represent effectively the typical miniaturized and smart features in traditional optical imaging field and the mature long-range and penetration detection capability in common radio frequency regime. As shown, the artificial patterned metamaterials demonstrate very high radiation responsing efficiency through coupling incident electromagnetic waves with so called the property of electromagnetic duality, as shown by terahertz waves, into the patterned micro-nano-photosensitive structures based on the high efficient resonance response of terahertz waves, and the physical properties of sensing incident electromagnetic wave-fields by particular micro-nano-metal structures. In this dissertation, firstly, the functioned metamaterials are designed and then fabricated and further used to sense terahertz signals, and thus the crucial problems related to the fundamental theories and essential methods and key technologies, are resolved, and therefore the developed detection methods are extended to integrated sense electromagnetic signals in both optical and radio frequency regime. The main contents are as follows:Firstly, the functioned metamaterials with patterned electrodes are carefully researched based on the transmission line theory. A comprehensive model has been constructed for simulating the basic characteristics of the key split resonance rings with particular shape and layout and line width and the number of split gaps with corresponding dimensions and distribution period, and also including the permittivity and thickness and conductivity of metal electrodes fabricated, the electron concentration and dielectric constant of gallium arsenide substrate, the boundary conditions and the polarization direction of incident electromagnetic wave-fields. A frequency-domain finite element method is used to simulate the terahertz transmission behaviors of the metamaterials developed so as to ensure demonstrating needed sensing characteristics of terahertz waves through typed metamaterials. According to the models and the size of gallium arsenide substrate utilized, the appropriate photolithographic layout for fabrication the Schottky-typed metamaterial devices have been designed. In order to solve the peeling problems in photolithographic processes, which is determined by the shin and brittle features of Ga As wafer, and the densely distributed narrowed connection wires and convex or concave angles of patterned metal electrodes, a cascade spread positive and negative photoresist method are applied to efficiently fabricate the metamaterial devices. The fabrication techniques based on the complex patterned Schottky-typed metamaterial devices, are developed through welding the metamaterial devices and their electrodes over the split gap circuit boards by extremely narrow gold wires.Then, the terahertz transmission experiments are carried out based on checking the electronic properties of the Schottky-typed metamaterials with different patterned micro-structure electrodes and split gaps and morphology characters. The photo-electronic responsing researches of the functioned metamaterial devices for sensing single-frequency terahertz lasers are conducted. The relationships between the terahertz sensing efficiency, the global and local transmission peak characters, the electrode layouts, the interface arrangement, and the electronic configuration of metamaterial devices, are analyzed fully.The researches about responsing broadband terahertz waves through functioned metamaterials are investigated deeply. The wide frequency terahertz waves generated by In As crystal are measured through patterned metamaterial devices with different electrode patterns, and then the spectral characteristics of transmitted waves are analyzed, and the patterned Schottky-typed metamaterial device technologies based on the dipole resonance behaviors are acquired. Besides, the wide frequency terahertz waves out from Ga As photoconductive antenna are also measured by using the functioned metamaterials composed of different patterned electrodes. The relationship between the amplitude enhancement of the transmitted terahertz responsing signals and the applied external voltage is discussed. The technological processes of the dual-mode resonance-typed(Fabry-Perot resonance, surface plasmon resonance) metamaterial devices, which are used to sensing broadband terahertz waves, are established.The researches of utilizing functioned metamaterials to detect optical frequency infrared radiations have been further implemented. Under the conditions of using near-infrared lasers and blackbody and also adjusting main parameters such as the exposure time and the measuring distance in experiments, the transmitted image characters acquired using functioned metamaterials with different electrode patterns, are analyzed. The bright light points or spots with relatively large distribution density and high intensity and very small structural size, are discovered, which distribute over the top layer of devices' electrode zone without metal structures of metamaterials devices, so as to indicate a potential sensing manner of optical frequency infrared radiations based on functioned metamaterial. In addition, a preliminary detection study of metamaterial-based radio frequency millimeter wave signals has also been investigated, and the transmission images acquired using functioned metamaterials with different patterned electrodes at different exposure time, are obtained.Finally, the detection architectures based on Schottky-typed functioned metamaterials to sense infrared light, terahertz radiation, and radio frequency millimeter waves, are proposed, and further the issues including the basic detection theory, the physical architecture, and the fabrication approaches for construction an effective integration detection means of optical and radio frequency electromagnetic radiations, are also investigated so as to lay a concrete foundation for future researches.