温度对液晶波前校正器响应速度及LUT的影响研究

温度起伏会对液晶器件的相位调制特性、响应速度有影响,从而影响自适应光学系统中的液晶波前校正器的相位调制精度。针对该问题,本文研究了温度对512×512像素的硅基液晶波前校正器(LCOS)的LUT(look-up table)的影响,正是由于LUT的变化导致其相位调制特性不同;实验测量了不同温度下LCOS的时间和相位响应特性,由此计算了对应的LUT,利用最小二乘拟合方法对得到的数据进行拟合,给出了16～26℃范围内的关系式,利用此关系式可以获得该温度范围内不同温度下合理的LUT。我们在LCOS上施加闪耀光栅灰度图后,对不同LUT下入射光束的衍射效率分别进行测量,结果表明我们利用关系式内对应温度下的LUT取代LCOS中固定值的LUT方法可以克服温度的起伏带来的影响,提高LCOS的相位调制能力。本方法对于液晶器件在自适应光学、显示等领域的应用也有帮助。

Effect of temperature on LUT and response speed of liquid crystal wavefront corrector

The temperature variation can affect the phase modulation characteristics and response speed of the liquid crystal wavefront corrector of adaptive optics, thereby affect its phase modulation accuracy. To solve this problem, the influence of temperature on the LUT (look-up table) of a 512×512 pixel silicon-based liquid crystal wavefront corrector (LCOS) was measured experimentally and analyzed. It is due to the change of the LUT induced by temperature that changed the phase modulation characteristics of the LCOS. The experimental measurements of temperal and phase response of the LCOS were conducted at different temperatures. And the corresponding LUTs were calculated. We used the method of least squares fitting to fit the obtained results and obtained an expression for LUTs in the range of 16 to 26℃. As a result, we can get a reasonable LUT at arbitrary temperature ranged from temperature range. We use the blazed grating generated by liquid crystal to verify the diffraction efficiency of the incident beam. The results indicate that our method can overcome the effects of temperature variations and improve the phase modulation capability of the LCOS by using the LUT at the corresponding temperature instead of a fixed one. Our results are valuable for fields, such as liquid crystal adaptive optics, display and so on.