紫外焦平面阵列器件调制传递函数测试技术

Modulation Transfer Function Testing Technology of Ultraviolet Focal Plane Arrays Device

针对紫外焦平面阵列器件调制传递函数的测试需求,基于刀口扫描法,搭建了一套调制传递函数测试系统。采用SW-Cassegrain同心反射系统方案实现刀口在探测器表面清晰成像,经测试,在0~100 lp/mm范围内可以达到衍射极限。利用该系统对紫外焦平面阵列器件进行了实际测试,测试过程中采用调制传递函数曲线下面积值最大的原则实现刀口像的自动调焦,采用三项费米函数的拟合模型对边缘扩散函数数据进行拟合,提高了拟合精度。实验结果表明在器件奈奎斯特频率处的调制传递函数值为0.601,接近器件的理论极限值,同时在奈奎斯特频率范围内,调制传递函数测量值的相对标准偏差最大为1.8%,获得了很好的测量重复性。不确定度分析结果表明,该装置对紫外焦平面阵列器件调制传递函数测试的测量不确定度为6.2%,能够很好地满足实际应用需求。

Aiming at the test requierments of modulation transfer function for ultraviolet focal plane arrays,a system based on knife-edge scanning method is built to measure the modulation transfer function.Knifeedge is clearly imaged on the detector by a SW-Cassegrain reflective optical system and actual test shows that the optical system is near the diffraction-limitation in range of 0~100 lp/mm.An ultraviolet focal plane array device is tested by this system and the principle of maximum area under modulation transfer function curve is adopted to realize automatic focusing of knife edge image.The edge spread function curve is fitted by the model of three term Fermi function,which can effectively increase the fitting accuracy.Experimental results show that the measured modulation transfer function value of ultraviolet focal plane arrays is about 0.601,which is close to its theoretical limit.Meanwhile,the repeatability is good,and relative standard deviation of modulation transfer function whithin the Nyquist frequency range is about 1.8%.Uncertainty analysis indicate that maximum uncertainty of the equipment is about 6.2%,which can meet the needs of practical application.