The Study On Processing Technology Of Acousto-optic Tunable Filter

The spectral imaging technology is the perfect combination of the image analysis and the spectral, at the same time,is the perfect combination of the image analysis and the spectral analysis.In recent years, the researchers have been attracted more and more attentions on the technology of spectral imaging, for its application in the fields of the military detection, fine agriculture and biomedicine.The study on the Acousto-optic tunable filter is a new spectroscopic element.Currently,The spectral imaging of AOTF is still in trial and error.In our country, we begin the study in this aspect comparatively late. At present,our study has not entered the practical phase. We still need to do a great deal of studies. Therefore,with the Department of International Science and Technology Cooperation project requirements,the study on processing technology of AOTF is selected as the main studied object of this paper. Firstly,considering the device performance parameters indicators and requirements of the project,We determine the piezoelectric transducer-cut(X-cut LiNiO3), the thickness of the piezoelectric layer(16μm)and the bonding film(double AR coating) thickness parameters; We have done many theoretical basis of the key processing technologies required AOTF. These theories have made a foundation for the following study on the AOTF based hyperspectral imaging system.Utilizing the UNIPOL-802 plane polishing machine to research the piezoelectric crystal polishing process to find out the requirements of the satisfying technical programs. In the view of the type and thickness of the bonding layer material are not the same,according to the film properties,we determine the manner and process conditions of vacuum coating and identified the vacuum chrome,gold,indium process parameters.Meanwhile, the piezoelectric transducers is very thin, and the thickness error required higher. After the vacuum lamination, the shape of AOTF is rather special. We can not make direct thinning. For this issue,We proposed an invention of the fixture and method for chemical mechanical polishing crystal thinning. After the calibration of the structure and method, the piezoelectric crystal thickness reduction is up to 16.055μm,and the thickness error is 0.734μm. After this set of technology parameters,the results we obtained satisfied the needs of the project. The wide applications of the AOTF technology on the speatral imagingarea would be pushed. This study has played a good role in promoting the practical application of Acousto-optic tunable filter technology.