Digital Holographic Microscopy Methods For Measurement Research Of FPA Temperature Characteristic Curve

Focal plane array is the core part of infrared detector, it is composed of micro-cantilever array without substrate-free. After heated, micro cantilever drives the reflector mechanical changes and the reflector produced a deflection angle, each micro-cantilever array independently to make absorbed heat into readout for holographic optical system of thermal deformation, whereby thermal imaging of the object is obtained. In order to study the method of improving the performance of FPA, but also provide the technical basis for the promotion and use of such infrared components in the future, it necessary to measure temperature-characteristic curve.Due to each micro-cantilever array of FPA independently to make absorbed heat into mechanical deflection of reflector, combined with the reflector size is very small, traditional method is difficult to obtain good results. Compared with the traditional optical readout FPA method, the observation of the micro deformation of objects with digital holography has high sensitivity, non contact, good dynamic characteristics, and can improve the imaging quality. So we measured the curve with the digital holographic optical system.Due to the thermal deformation of measurement process which is a dynamic observation of micro unit, therefore the experiment research by using digital holographic microscopy measurement technology to make sample FPA reflector unit of amplification. Selection of reflecting digital holographic microscopy optical path, after splitting,the object light is irradiated to the FPA surface through the microscope objective and then reflected back through the microscope objective with reference interfere. Continuous change FPA temperature and recorded before and after deformation of the light field, calculating the shape variables through digital reconstruction,then the temperature-deformation characteristic curve of FPA reflector is finally obtained. We also obtain the thermal-mechanic sensitivity of FPA, which is consistent with the available data.