Article ID Journal Published Year Pages File Type
1533301 Optics Communications 2016 9 Pages PDF
Abstract

•We derive a formula for thermal deformation of an optical phase mask.•We propose an equivalent cubic phase mask (E-CPM).•Our model proves a Ge CPM achieves better PSF consistency than a ZnSe CPM.•Our model proves the effect of a phase mask on PSF inconsistency is much slighter.

The point spread function (PSF) inconsistency caused by temperature variation leads to artifacts in decoded images of a wavefront coding infrared imaging system. Therefore, this paper proposes an analytical model for the effect of temperature variation on the PSF consistency. In the proposed model, a formula for the thermal deformation of an optical phase mask is derived. This formula indicates that a cubic optical phase mask (CPM) is still cubic after thermal deformation. A proposed equivalent cubic phase mask (E-CPM) is a virtual and room-temperature lens which characterizes the optical effect of temperature variation on the CPM. Additionally, a calculating method for PSF consistency after temperature variation is presented. Numerical simulation illustrates the validity of the proposed model and some significant conclusions are drawn. Given the form parameter, the PSF consistency achieved by a Ge-material CPM is better than the PSF consistency by a ZnSe-material CPM. The effect of the optical phase mask on PSF inconsistency is much slighter than that of the auxiliary lens group. A large form parameter of the CPM will introduce large defocus-insensitive aberrations, which improves the PSF consistency but degrades the room-temperature MTF.

Related Topics
Physical Sciences and Engineering Materials Science Electronic, Optical and Magnetic Materials
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