Diffraction efficiency change of multilayer diffractive optics with environmental temperature

Abstract

In this paper, the effect of an environmental temperature change on multilayer diffractive optical elements (MLDOEs) is studied in terms of the diffraction efficiency and the polychromatic integral diffraction efficiency (PIDE). The relation between the diffraction efficiency of MLDOEs and environmental temperature is analyzed theoretically, and examples of different MLDOEs are discussed in the visible and infrared wavebands. The result shows that the diffraction efficiency reduction is no more than 5% and the PIDE reduction is less than 1.5% for optical plastic MLDOEs in the visible waveband when the environmental temperature ranges from −62 to 71 • C, and that the decrease of both the diffraction efficiency and PIDE for MLDOEs is more significant in the mid-wave infrared than in the long-wave infrared. The analysis result can be considered during optical engineering design with MLDOEs.

Computational Imaging in Dual-Band Infrared Hybrid Optical System with Wide Temperature Range

“…In some special cases, the ambient temperature of the two substrate materials of the DLDOE is different, but in most cases, processes covering design, manufacture and assemble are always at the same ambient temperature. Considering the influence of ambient temperature on diffractive micro-structure heights is much greater than that of the longitudinal dimensions, the effects of the diffractive micro-structure heights on its diffraction efficiency caused by ambient temperature is more obvious than that of the longitudinal dimension changes [ 10 ]. The micro-structure height for each layer of DLDOE is ten times or more that of the traditional single-layer DOE, so the micro-structure heights of the DLDOE and the refractive index of the base material are changing with ambient environment, which will significantly affect its diffraction efficiency, resulting in the inability to achieve high-quality imaging at different ambient temperatures.…”

“…The object can be regarded as a collection of many point lights, all of which are in the linear superposition set of the light intensity distribution formed by the point spread function (PSF) through the imaging optical system. So, to describe the imaging process, a set of point light sources in the object and the point diffusion function of the system to do convolution is presented, expressed as [14] g(x, y) = x PSF (x, y) ⊗ f (x, y) + η(x, y) (10) where g(x,y) is the simulation plot, f (x,y) is the light source bitmap, x psf (x,y) is the degenerate function, and η(x,y) is noise. Since the simulation graph g(x,y) is obtained by convolving the light source bitmap f (x,y) with the degradation function of the system, x psf (x,y), the effect of noise is not taken into account here.…”

Motionless and fast measurement technique for obtaining the spectral diffraction efficiencies of a grating

“…22,35 (b) For many practical applications of diffraction gratings, environmental parameters, such as temperature and humidity, have a non-negligible influence on the microstructure of the grating and, thus, affect the grating's spectral diffraction efficiencies. [36][37][38] Hence, the dynamic measurement of the grating's spectral diffraction efficiencies in the case, for example, of changing the environmental temperature would provide abundant data on ways to effectively utilize the grating in different environments. (c) In mass industrial manufacturing, the spectral diffraction efficiencies of the grating need to be obtained rapidly to increase the production efficiency.…”

Chromatic analysis of harmonic Fresnel lenses by FDTD and angular spectrum methods

“…However, the stack of DOEs can only increase the broadband efficiency. The Abbe number is still around -3.5 [4][5][6][7][8]. A harmonic Fresnel lens (HFL) or multi-order diffractive lens can keep high diffraction efficiency and constant focal length at several discrete wavelengths [9,10].…”