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We have proposed an approach for rapid generation of perfect vortex beam without side lobes through a digital micromirror device (DMD). Employing this method, the amplitude and phase of far field can be controlled indirectly by changing the rotation state of each unit on the DMD. The perfect vortex beams of equal rings diameter independent of their topological charges are generated commendably and the side lobes are avoided. Moreover, we have demonstrated rapid switching among the generated orbital angular momentum modes at the speed of 10 kHz, which is much faster than that of the usual method realized by spatial light modulators (SLMs). The proposed method is very beneficial for the optical communication and trapping or manipulating the small particle based on orbital angular momentum modes. [ABSTRACT FROM AUTHOR]

The digital micromirror device (DMD) is an array of tilting micromirrors, capable of high frame rates that are made possible by rapid changes of angular state. The rapid angular change of the mirrors is used to sweep an optical signal across a camera sensor, resulting in a version of a streak camera, capable of temporal dispersion of an optical signal. Using a single pixel or single line of pixels can produce a continuous temporal track, whereas a two-dimensional array of mirrors scans an intensity envelope across discrete diffraction orders. Temporal resolutions of 10nS have been achieved and used to measure laser pulse widths. Combining with a diffraction grating oriented orthogonally to the temporal dispersion enables temporal and spectral dispersion to be obtained simultaneously. [ABSTRACT FROM AUTHOR]

A digital micromirror device (DMD) acts as a spatial light modulator in a maskless photolithography system. Illuminated by coherent light, DMD performs as a two-dimensional diffraction grating because of its periodical internal structure. Diffraction efficiency is an important factor for evaluating the exposure doses. A diffraction model of DMD based on Fourier analysis demonstrates that errors of the DMD's manufacture and the precision of the machining of the optical mechanical structure affect the diffraction efficiency. Additionally, analysis of exposure results by the diffraction model of DMD in Tracepro explains the degradation of the exposure quality and is helpful for calibrating the direction of optical focusing. [ABSTRACT FROM AUTHOR]

This paper reports on the measurement system of the phase difference between s- and p-polarization components of the light passing through a guided-mode resonance (GMR) device using a digital micromirror device (DMD) gratings as a digital phase-shifting device. The phase of the non-zeroth order diffraction beams of the grating pattern displayed on the DMD can exhibit a phase change when the grating pattern is shifted. Two nearest different diffraction orders of p-polarized and s-polarized beams can be used as the reference and measurement beams, respectively, and are combined to implement the phase-shifting interferometry (PSI). The phase difference between the s- and the p-polarization components of the incident light passing through the GMR device can be obtained by applying the four-step phase-shift algorithm to the DMD-based PSI system. Experimental results show that this measurement system has a phase detection limit of 1° and was able to obtain the abrupt phase difference curve of the GMR device versus the incident angle. [ABSTRACT FROM AUTHOR]