The Detection Method Of Electronically Adjusted Spectral Imaging In Infrared Region And The Study Of The Key Technology Of Spectral Device

This thesis proposes a novel electrically adjusted spectral imaging detection method andcorrespondent spectral device. The key cascade spectral imaging devices in mid-infrared (MIR) region,are based on the principle of electrically controlled liquid crystal Fabry-Perot (LC-FP) interferometer,and the wavelength of incident light beam can be shifted and adjusted by the electric field signal appliedover the LC-FP as above. We discuss the typical characters of the electrically adjusted LC-FP chipcompared to the conventional Micro-Electro-Mechanical Systems (MEMS-FP) architecture. Generally,the MEMS-FP structures need mechanical translation operation to realize the wavelength choice ofincident beam, so as to must moving the optical plate of MEMS-FP to fixed position, and thereforeoutput the selected spectroscopic component, and finally completion the spectral imaging detection. TheLC-FP devices only require a voltage regulator and thus the wavelength choice of output beamsaccording to the LC-FP can be quickly carried out, which means the device will demonstrate a very highstructural stability.Based on the effect of the directing vector distribution of LC materials can be remarkably changedin the electric field applied over LC structures, the refractive index of the LC materials filled into FPcavity can be modulated when the voltage signal applied over the electrodes of the LC-FP is changed.The key features of the proposal approach is as follows: the devices are mainly composed of very thinelectrically modulating refractive-index architecture, which show a type of hybrid integrated structurebased on two basic FP interferometers connected closely and accurately performing the interferencefiltering. The depths of both FP interferometers are designed to be different. Through applying voltagesignal with definite amplitude and cycle, we can obtain beams with desired wavelength for next imagingdetection operation.After putting LC materials into fabricated cavity with a depth in nanometer size and both top andbottom electrodes and the dielectric mirrors with convectional alignment films, the MIR LC-FP devicesare constructed. Because the aluminum (Al) electrode material has a very high reflectance, the materialsof dielectric mirrors is further replaced by Al and then Al mirrors are also be used as electrodes of LC-FPdevices. Because the transmissivity of substrates should be very high, we choose zinc selenide as wafermaterials.We obtain MIR LC-FP device according to the standard semiconductor technology and thetechnique which is slightly different in the process of fabrication single chip device and cascade device.According to the optical measurement platform setup by us, when the different signal voltages areapplied on the device, the phenomena that the image brightness will generate remarkable variancecorrespondent to the change of the signal voltage and the extent between the brightness to darkness ofthe patterns also generate correspondent change, and then the pattern edge turn to be dim. Theexperiments show that the signal voltage demonstrate remarkable adjustment operation to the refractiveindex of liquid crystal materials, and both single chip and cascade LC-FP interferometer show theselection imaging wavelength effect in mid-infrared range.We also discuss and analyze carefully the device technology utilized, and demonstrate key parameters of the main components of developed device, including key transmittance of both thesubstrate and electrodes used, and several technological problems encountered in the process offabrication device and carrying out measurements, and finally indicate some existing problems andfurther improvement methods for devices developed.