Digital micromirror device for holographic and Fourier optics applications

The electromagnetic wavefront diffracted by an object carries information about the shape of the object from which the wave was emitted. Being able to record the phase and intensity of such a wave thus allows to reconstruct the object from the information carried by the wave, even if the object is no longer present. Among the reconstruction techniques, holography plays a big part. However the waves may experience a great variety of distortions on their way from the object to the measurement apparatus. Thus being able to shape the wavefront at will is key in holography. Micromirror light modulators are powerful tools for that matter and are well known for holographic applications. This paper explores the fundamental principles for digitally reconstructing a precise image of an object, but also for digitally correcting an imperfectly shaped wavefront, by exploiting the diffraction properties of light on a reflective surface. The methods presented here have been implemented as part of practical work for 2nd year students at the Ecole Polytechnique (last year of undergraduate program).

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Rapid generation of perfect vortex beam without side lobes

Modern Physics Letters B ◽

10.1142/s0217984918502895 ◽

2018 ◽

Vol 32 (24) ◽

pp. 1850289

Author(s):

Siqi Li ◽

Mulong Liu ◽

Xingyi Li ◽

Zhiqiang Ge ◽

Lingxuan Zhang

Keyword(s):

Angular Momentum ◽

Orbital Angular Momentum ◽

Optical Communication ◽

Spatial Light Modulators ◽

Vortex Beam ◽

Digital Micromirror Device ◽

Light Modulators ◽

Rapid Generation ◽

Rapid Switching ◽

Topological Charges

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.

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Applications of Spatial Light Modulators in Raman Spectroscopy

Applied Spectroscopy ◽

10.1177/0003702819834575 ◽

2019 ◽

Vol 73 (7) ◽

pp. 727-746 ◽

Cited By ~ 8

Author(s):

Faris Sinjab ◽

Zhiyu Liao ◽

Ioan Notingher

Keyword(s):

Raman Spectroscopy ◽

Adaptive Optics ◽

Laser Excitation ◽

Spatial Light Modulators ◽

Digital Micromirror Device ◽

Spectral Filtering ◽

Fast Detection ◽

Light Modulators ◽

Sampling Volume ◽

Selection Of

Advances in consumer display screen technologies have historically been adapted by researchers across the fields of optics as they can be used as electronically controlled spatial light modulators (SLMs) for a variety of uses. The performance characteristics of such SLM devices based on liquid crystal (LC) and digital micromirror device (DMD) technologies, in particular, has developed to the point where they are compatible with increasingly sensitive instrumental applications, for example, Raman spectroscopy. Spatial light modulators provide additional flexibility, from modulation of the laser excitation (including multiple laser foci patterns), manipulation of microscopic samples (optical trapping), or selection of sampling volume (adaptive optics or spatially offset Raman spectroscopy), to modulation in the spectral domain for high-resolution spectral filtering or multiplexed/compressive fast detection. Here, we introduce the benefits of different SLM devices as a part of Raman instrumentation and provide a variety of recent example applications which have benefited from their incorporation into a Raman system.

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Rapid detection of highly reflective surface defects based on digital micromirror device

Optics Communications ◽

10.1016/j.optcom.2021.127385 ◽

2021 ◽

pp. 127385

Author(s):

Bin Niu ◽

Xinghua Qu ◽

Xiaomei Guan ◽

Fumin Zhang

Keyword(s):

Rapid Detection ◽

Surface Defects ◽

Digital Micromirror Device ◽

Reflective Surface

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Use of the Magnetostatic Analogue In Electromagnetic Lens Engineering

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100068795 ◽

1970 ◽

Vol 28 ◽

pp. 360-361

Author(s):

John W. Coleman

Keyword(s):

Boundary Conditions ◽

High Performance ◽

Force Fields ◽

Optical Design ◽

Direct Conversion ◽

Design Engineering ◽

Design Data ◽

Scalar Potentials ◽

Geometric Elements ◽

At Will

In the design engineering of high performance electromagnetic lenses, the direct conversion of electron optical design data into drawings for reliable hardware is oftentimes difficult, especially in terms of how to mount parts to each other, how to tolerance dimensions, and how to specify finishes. An answer to this is in the use of magnetostatic analytics, corresponding to boundary conditions for the optical design. With such models, the magnetostatic force on a test pole along the axis may be examined, and in this way one may obtain priority listings for holding dimensions, relieving stresses, etc..The development of magnetostatic models most easily proceeds from the derivation of scalar potentials of separate geometric elements. These potentials can then be conbined at will because of the superposition characteristic of conservative force fields.

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Resistance Monitor and Control for Vacuum Evaporation of Metals and Carbon

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092827 ◽

1976 ◽

Vol 34 ◽

pp. 572-573

Author(s):

Russell L. Steere ◽

Eric F. Erbe ◽

J. Michael Moseley

Keyword(s):

Electronic Device ◽

Point Sources ◽

High Contrast ◽

Variable Resistor ◽

Quality Of Results ◽

Low Contrast ◽

Evaporation Source ◽

And Control ◽

At Will

We have designed and built an electronic device which compares the resistance of a defined area of vacuum evaporated material with a variable resistor. When the two resistances are matched, the device automatically disconnects the primary side of the substrate transformer and stops further evaporation.This approach to controlled evaporation in conjunction with the modified guns and evaporation source permits reliably reproducible multiple Pt shadow films from a single Pt wrapped carbon point source. The reproducibility from consecutive C point sources is also reliable. Furthermore, the device we have developed permits us to select a predetermined resistance so that low contrast high-resolution shadows, heavy high contrast shadows, or any grade in between can be selected at will. The reproducibility and quality of results are demonstrated in Figures 1-4 which represent evaporations at various settings of the variable resistor.

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The Waves

10.1017/cbo9780511553783 ◽

1986 ◽

Cited By ~ 8

Author(s):

Virginia Woolf ◽

Warner

Keyword(s):

The Waves

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A Model for Analyzing Suicide Prevention

Crisis ◽

10.1027//0227-5910.21.2.80 ◽

2000 ◽

Vol 21 (2) ◽

pp. 80-89 ◽

Cited By ~ 3

Author(s):

Maila Upanne

Keyword(s):

Risk Factors ◽

Theoretical Model ◽

Protective Factors ◽

Suicide Prevention ◽

Suicide Risk ◽

Practical Work ◽

Individual Risk ◽

Self Assessment ◽

Prevention Project ◽

Individual Risk Factors

This study monitored the evolution of psychologists' (n = 31) conceptions of suicide prevention over the 9-year course of the National Suicide Prevention Project in Finland and assessed the feasibility of the theoretical model for analyzing suicide prevention developed in earlier studies [ Upanne, 1999a , b ]. The study was formulated as a retrospective self-assessment where participants compared their earlier descriptions of suicide prevention with their current views. The changes in conceptions were analyzed and interpreted using both the model and the explanations given by the subjects themselves. The analysis proved the model to be a useful framework for revealing the essential features of prevention. The results showed that the freely-formulated ideas on prevention were more comprehensive than those evolved in practical work. Compared to the earlier findings, the conceptions among the group had shifted toward emphasizing a curative approach and the significance of individual risk factors. In particular, greater priority was focused on the acute suicide risk phase as a preventive target. Nonetheless, the overall structure of prevention ideology remained comprehensive and multifactorial, stressing multistage influencing. Promotive aims (protective factors) also remained part of the prevention paradigm. Practical working experiences enhanced the psychologists' sense of the difficulties of suicide prevention as well as their criticism and feeling of powerlessness.

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