Diffraction analysis for DMD-based scene projectors in the long-wave infrared

Abstract

Diffraction effects play a significant role in the digital micromirror device (DMD)-based scene projectors in the long-wave infrared (IR) band (8-12 μm). The contrast provided by these projector systems can become noticeably worse because of the diffraction characteristics of the DMD. We apply a diffraction grating model of the DMD based on the scalar diffraction theory and the Fourier transform to address this issue. In addition, a simulation calculation is conducted with MATLAB. Finally, the simulation result is verified with an experiment. The simulation and experimental results indicate that, when the incident azimuth angle is 0° and the zenith angle is between 42°and 46°, the scene projectors will have a good imaging contrast in the long-wave IR. The diffraction grating model proposed in this study provides a method to improve the contrast of DMD-based scene projectors in the long-wave IR.

Diffraction Characteristics of a Digital Micromirror Device for Computer Holography Based on an Accurate Three-Dimensional Phase Model

“…Some studies have considered the phase difference; however, the diffraction envelopes described by the models in these works were not accurate enough [24,25]. Some studies have analyzed DMD by developing a two-dimensional (2D) reflectance function, while there were many inconsistencies in the details of the equations among them [26][27][28][29][30]. Most studies have focused on the intensity distribution of the diffraction field of DMD, while ignoring the phase properties of the diffraction field [23][24][25][26][27][28][29][30].…”

A Robust Infrared Transducer of an Ultra-Large-Scale Array

“…Table 1 presents the comparison of widely used infrared image generation technologies. DMD is restricted by diffraction in the long wave IR band although it can achieve desired frame rate [31,32]. Limited by the complicated read-in integrated circuits, the maximum pixels of single resistor array are 512 × 512.…”