Search

INdian Spectroscopic and Imaging Space Telescope (INSIST) is the next-generation UV-Optical space mission proposed by the Indian Astronomical community motivated by the great success of India's first multi-wavelength Astronomical satellite (ASTROSAT) where Ultra Violet Imaging Telescope (UVIT) was one of the main payload launched in 2015 by Indian Space Research Organisation. INSIST is primarily designed for photometry observation in three bands (g-[400 nm–550 nm], u-[300 nm–400 nm] and UV-[150 nm–300 nm]) simultaneously over 0.25 sq.degree field of view. INSIST is equipped with a low resolution [ R ∼ 5 0 0 ] spectrograph for multi-Object slitless spectroscopy over the imaging field of view and also has a medium resolution [ R ∼ 2 0 0 0 ] spectrograph for multi-object slit spectroscopy in UV-band over ∼6 sq.arcmin sky. MEMS-based Digital Micromirror Device [DMD] is used to form configurable slits for the selection of objects at the focal plane of the telescope for multi-object slit spectrograph. Multi-Object spectrograph with DMD as a re-configurable slit for INSIST is designed and the performance of the spectrograph is presented. [ABSTRACT FROM AUTHOR]

There is an ongoing technological revolution in the field of biomedical instruments. Consequently, high performance healthcare devices have led to remarkable economic developments in the medical hardware industry. Until now, nearly all optical bio-imaging systems are based on the 2-dimensional imaging chip architecture. In fact, recent developments in digital micromirror devices (DMDs) are gradually making their way from conventional optical projection displays into biomedical instruments. As an ultrahigh-speed spatial light modulator, the DMD may offer a range of new applications including real-time biomedical sensing or imaging, as well as orientation tracking and targeted screening. Given its short history, the use of DMD in biomedical and healthcare instruments has emerged only within the past decade. In this paper, we first provide an overview by summarizing all reported cases found in the literature. We then critically analyze the general pros and cons of using DMD, specifically in terms of response speed, stability, accuracy, repeatability, robustness, and degree of automation, in relation to the performance outcome of the designated instrument. Particularly, we shall focus our discussion on the use of Micro-Electro-Mechanical System (MEMS)-based devices in a set of representative instruments including the surface plasmon resonance biosensor, optical microscopes, Raman spectrometers, ophthalmoscopes, and the micro stereolithographic system. Finally, the prospects of using the DMD approach in biomedical or healthcare systems and possible next generation DMD-based biomedical devices are presented. [ABSTRACT FROM AUTHOR]

Structured illumination microscopy (SIM) is a promising super-resolution technique for imaging subcellular structures and dynamics due to its compatibility with most commonly used fluorescent labeling methods. Structured illumination can be obtained by either laser interference or projection of fringe patterns. Here, we proposed a fringe projector composed of a compact multi-wavelength LEDs module and a digital micromirror device (DMD) which can be directly attached to most commercial inverted fluorescent microscopes and update it into a SIM system. The effects of the period and duty cycle of fringe patterns on the modulation depth of the structured light field were studied. With the optimized fringe pattern, 1. 6 × resolution improvement could be obtained with high-end oil objectives. Multicolor imaging and dynamics of subcellular organelles in live cells were also demonstrated. Our method provides a low-cost solution for SIM setup to expand its wide range of applications to most research labs in the field of life science and medicine. [ABSTRACT FROM AUTHOR]

An ultrafast spectrum programmable femtosecond laser may enhance the performance of a wide variety of scientific applications, e.g., multi-photon imaging. In this paper, we report a digital micromirror device (DMD)-based ultrafast pulse shaper, i.e., DUPS, for femtosecond laser arbitrary amplitude shaping — the first time a programmable binary device reported to shape the amplitudes of ultrafast pulses spectrum at up to 32 kHz rate over a broad wavelength range. The DUPS is highly efficient, compact, and low cost based on the use of a DMD in combination with a transmission grating. Spatial and temporal dispersion introduced by the DUPS is compensated by a quasi-4-f setup and a grating pair, respectively. Femtosecond pulses with arbitrary spectrum shapes, including rectangular, sawtooth, triangular, double-pulse, and exponential profile, have been demonstrated in our experiments. A feedback operation process is implemented in the DUPS to ensure a robust and repeatable shaping process. The total efficiency of the DUPS for amplitude shaping is measured to be 27%. [ABSTRACT FROM AUTHOR]

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]

In the current paper, the effect of van der Waals (vdW) force on the static behavior and pull-in characteristics of nano/micromirrors under capillary force is investigated. At first, the dimensionless equation governing the static behavior of nano/micromirrors is obtained. The dependence of the critical tilting angle on the physical and geometrical parameters of the nano/micromirror and its supporting torsional beams is investigated. It is found that the existence of vdW force can considerably reduce the stability limits of the nano/micromirror. It is also found that rotation angle of the mirror due to capillary force highly depends on the vdW force applied to the mirror. Finally, analytical tool Homotopy Perturbation Method (HPM) is utilized for prediction of the nano/micromirror behavior under combined capillary and vdW force. It is observed that a sixth order perturbation approximation accurately predicts the rotation angle and stability limits of the mirror. The results of this paper can be used for successful fabrication of nano/micromirrors using wet etching release process where capillary force plays a major role in the system. [ABSTRACT FROM AUTHOR]