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Multimode fibers (MMFs), which transmit multiple spatial modes simultaneously, are essential in imaging, communication, and sensing. However, mode crosstalk significantly impairs the clarity of transmitted signals. Wavefront shaping has emerged as an effective strategy to minimize these distortions. Given the dynamic environmental conditions under which MMFs operate, rapid technological adaptation is crucial. A high‐speed full‐field wavefront shaping system designed for real‐time MMF control is developed. This system leverages probabilistic phase shaping, superpixel modulation, and a digital micromirror device (DMD) to achieve operational speeds of 38 ms per cycle for 400 spatial modes, translating to an average mode time of 95 µs. This rate sets a new record for DMD‐based systems, pushing hardware limits. The system supports continuous operation at 11 Hz and maintains high‐quality optical focus through MMFs under varying environmental conditions, with a focusing efficiency exceeding 50% of the theoretical maximum. Its compatibility with fluorescent guide stars enables transmission matrix characterization when direct access is unfeasible, broadening its applications. This high‐speed full‐field wavefront shaping system represents a significant breakthrough, enhancing the functionality and versatility of MMF‐based applications. [ABSTRACT FROM AUTHOR]

With the increasing acquisition speed of image sensors, it has become necessary to provide image sources with higher frame rates and grayscale in order to meet testing requirements. In the field of semi-physical simulation projection, digital micromirror devices are often chosen for their high resolution, uniformity, response speed, and energy concentration. In this study, we utilized digital micromirror devices to construct a high-frame-rate and large-grayscale simulation projection system. To achieve our experiment goals, we employed two digital micromirror devices. One DMD was used to modulate the light intensity of the light source, while the other generated images with different bit planes. By projecting the target images onto the image sensor, we were able to achieve a frame rate of 1611 hz for the projected 12-bit image. This system meets the requirements for our experiment design and ensures the accurate testing of image sensors. [ABSTRACT FROM AUTHOR]

The growing interest in the application of structured light has led to an increase in the use of spatial light modulators across users at all levels of experience. Hence, there is a need for software that controls the device, designs holograms and gathers experimental feedback. To meet these demands we present the Binary Complex Amplitude App - a standalone Matlab application that provides a graphic user interface with a full control of the Digital Micromirror Device, enabling hologram design and camera preview. We show that with all-in-one application, the user at any level of experience can operate the device and do not lose any of its capabilities.

Using structured light to drive colloidal motors, due to its advantages of remote manipulation, energy tunability, programmability, and the controllability of spatiotemporal distribution, has been attracting much attention in the fields of targeted drug delivery, environmental control, chemical agent detection, and smart device design. Here, we focus on studying the group control of colloidal motors made from a photo-responsive organic polymer molecule NO-COP (N,O-Covalent organic polymer). These colloidal motors mainly respond to light intensity patterns. Considering its merits of fast refreshing speed, good programmability, and high-power threshold, we chose a digital micromirror device (DMD) to modulate the structured light field shining on the sample. It was found that under ultraviolet or green light modulation, such colloidal motors exhibit various group behaviors including group spreading, group patterning, and group migration. A qualitative interpretation is also provided for these observations. [ABSTRACT FROM AUTHOR]

Photonic crystal (PC) hydrogels with unique micro/nanostructures have excellent prospects in many fields, such as sensing, displays, anticounterfeiting, information encryption, and adaptive camouflage. Herein, magnetic core–shell Fe3O4/SiO2 nanoparticles with a controlled size were synthesized, followed by PC hydrogels of arbitrary structures that were fabricated via the magnetically inducing self-assembly of magnetic nanoparticles in the poly-(ethylene glycol) diacrylate (PEGDA) pregel solution and a subsequent digital micromirror device (DMD)-based UV polymerization process. By controlling the size of nanoparticles and magnetic field intensity, various PC hydrogel patterns with tunable structural colors were fabricated. Combining magnetic field control with DMD-based light modulation, high-throughput preparation of structural color PC hydrogels was achieved. Furthermore, the Fe3O4/SiO2 nanoparticles were assembled into poly-(2-hydroxyethyl methacrylate) (PHEMA) with solvent responsiveness. Interestingly, the obtained PC hydrogels could swell in ethanol, resulting in a change in the structural color. Meaningfully, a dual-component PC hydrogel consisting of a PEGDA pattern and a PHEMA background was fabricated, and the invisible pattern in the initial state could be displayed and hidden through cyclic exposure to ethanol and ethylene glycol. The presented strategy for constructing the PC hydrogels from Fe3O4/SiO2 nanoparticles could provide valuable insights for the development of intelligent structural color materials, which exhibit significant potential in applications such as information storage, visual sensing, and anticounterfeiting. [ABSTRACT FROM AUTHOR]

Maskless UV photolithography is increasingly used, especially in research environments where low turn-around time for new designs improves productivity. Here, we fabricate pyrolytic carbon interdigitated microelectrodes with small interelectrode gaps, good adhesion to the carrier substrate, high surface area and excellent electrochemical properties using maskless UV photolithography with two negative epoxy-based photoresists, namely the commonly used SU-8 and the recently developed mr-DWL. The minimum realizable trench width in 15 μm thick photoresist films is 2.4 ± 0.15 μm for mr-DWL 5 and 3.1 ± 0.10 μm for SU-8 2035. After pyrolysis, the two resulting pyrolytic carbon materials show similar electrochemical properties. However, shrinkage during pyrolysis is significantly lower for mr-DWL compared to SU-8, which is beneficial for the fabrication of interdigitated microelectrodes. Furthermore, delamination of the electrodes during processing and operation is prevented due to the introduction of poly silicon adhesion structures. This work provides valuable insights into maskless UV lithography as well as into the pyrolytic carbon process to increase the yield, performance and productivity for fabrication of microelectrodes.

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]

With the increasing acquisition speed of image sensors, it has become necessary to provide image sources with higher frame rates and grayscale in order to meet testing requirements. In the field of semi-physical simulation projection, digital micromirror devices are often chosen for their high resolution, uniformity, response speed, and energy concentration. In this study, we utilized digital micromirror devices to construct a high-frame-rate and large-grayscale simulation projection system. To achieve our experiment goals, we employed two digital micromirror devices. One DMD was used to modulate the light intensity of the light source, while the other generated images with different bit planes. By projecting the target images onto the image sensor, we were able to achieve a frame rate of 1611 hz for the projected 12-bit image. This system meets the requirements for our experiment design and ensures the accurate testing of image sensors.

High-intensity vortex beams with tunable topological charges and low coherence are highly demanded in applications such as inertial confinement fusion (ICF) and optical communication. However, traditional optical vortices featuring nonuniform intensity distributions are dramatically restricted in application scenarios that require a high-intensity vortex beam owing to their ineffective amplification resulting from the intensity-dependent nonlinear effect. Here, a low-coherence perfect vortex beam (PVB) with a topological charge as high as 140 is realized based on the super-pixel wavefront-shaping technique. More importantly, a globally adaptive feedback algorithm (GAFA) is proposed to efficiently suppress the original intensity fluctuation and achieve a flat-top PVB with dramatically reduced beam speckle contrast. The GAFA-based flat-top PVB generation method can pave the way for high-intensity vortex beam generation, which is crucial for potential applications in ICF, laser processing, optical communication and optical trapping.

Using structured light to drive colloidal motors, due to its advantages of remote manipulation, energy tunability, programmability, and the controllability of spatiotemporal distribution, has been attracting much attention in the fields of targeted drug delivery, environmental control, chemical agent detection, and smart device design. Here, we focus on studying the group control of colloidal motors made from a photo-responsive organic polymer molecule NO-COP (N,O-Covalent organic polymer). These colloidal motors mainly respond to light intensity patterns. Considering its merits of fast refreshing speed, good programmability, and high-power threshold, we chose a digital micromirror device (DMD) to modulate the structured light field shining on the sample. It was found that under ultraviolet or green light modulation, such colloidal motors exhibit various group behaviors including group spreading, group patterning, and group migration. A qualitative interpretation is also provided for these observations.

Digital optical phase conjugation (DOPC) is considered as a promising solution to achieve optical focusing against scattering. The implementation of DOPC based on the digital micromirror device (DMD) has been proven to have great potential, supporting a large number of modulation modes and a high modulation rate. However, the accuracy of optical alignment seriously affects the focusing contrast, limiting the applications of DMD-based DOPC systems. Here we demonstrate a simple alignment protocol including a marker-assisted tuning and an embedded compensation. Our approach can realize an exact pixelwise optical conjugation between the DMD and detector, as well as a rapid compensation for aberrations and minor misalignment. Experimental results show that the proposed alignment protocol improves the focusing contrast to 66% of the highest value predicted in the theory.

Localized actuation is an important goal of nanotechnology broadly impacting applications such as programmable materials, soft robotics, and nanolithography. Despite significant recent advances, actuation with high temporal and spatial resolution remains challenging to achieve. Herein, we demonstrate strongly localized photoactuation of polymer pens made of polydimethylsiloxane (PDMS) and surface-functionalized short carbon nanotubes based on a fundamental understanding of the nanocomposite chemistry and device innovations in directing intense light with digital micromirrors to microscale domains. We show that local illumination can drive a small group of pens (3 × 3 over 170 μm × 170 μm) within a massively two-dimensional array to attain an out-of-plane motion by more than 7 μm for active molecular printing. The observed effect marks a striking three-order-of-magnitude improvement over the state of the art and suggests new opportunities for active actuation. [ABSTRACT FROM AUTHOR]

Fast reconstruction of holographic and diffractive optical elements (DOE) can be implemented by binary digital micromirror devices (DMD). Since micromirrors of the DMD have two positions, the synthesized DOEs must be binary. This work studies the possibility of improving the method of synthesis of amplitude binary inline Fresnel holograms in divergent beams. The method consists of the modified Gerchberg–Saxton algorithm, Otsu binarization and direct search with random trajectory technique. To achieve a better quality of reconstruction, various binarization methods were compared. We performed numerical and optical experiments using the DMD. Holograms of halftone image with size up to 1024 × 1024 pixels were synthesized. It was determined that local and several global threshold methods provide the best quality. Compared to the Otsu binarization used in the original method of the synthesis, the reconstruction quality (MSE and SSIM values) is improved by 46% and the diffraction efficiency is increased by 27%. [ABSTRACT FROM AUTHOR]

Focusing light inside scattering media has many applications and can be realized by the iterative method optimizing the wavefront of incident light. However, this method often achieves a moderate contrast of focus, which compromises its performance. Here, we propose full-polarization iterative wavefront shaping (FPI-WS) in which we adopt two digital micromirror devices. By modulating the two orthogonal polarization components independently, this method adds one more degree of freedom shaping the wavefront. In comparison with the previous result, FPI-WS can increase the peak to background ratio of focus by a factor of two. [ABSTRACT FROM AUTHOR]

In a lidar system, replacing moving components with solid-state devices is highly anticipated to make a reliable and compact lidar system, provided that a substantially large beam area with a large angular extent as well as high angular resolution is assured for the lidar transmitter and receiver. A new quasi-solid-state lidar optical architecture employs a transmitter with a two-dimensional MEMS mirror for fine beam steering at a fraction of the degree of the angular resolution and is combined with a digital micromirror device for wide FOV scanning over 37 degree while sustaining a large aperture area of 140 mm squared. In the receiver, a second digital micromirror device is synchronized to the transmitter DMD, which enables a large FOV receiver. An angular resolution of 0.57 ° (H)   by 0.23 °   (V) was achieved with 0.588 fps for scanning 1344 points within the field of view. [ABSTRACT FROM AUTHOR]

We proposed an efficient and low-cost compensation method for improving exposure uniformity. A flexible designed uniformity grayscale template compensation strategy based on digital micromirror device oblique scanning lithography was developed, which can effectively improve exposure region uniformity. In order to avoid the asynchronous error of the exposure process, the light-source synchronization control based on the pulse width modulation strategy was introduced in the lithography system. The experimental results showed that the maximum dimensional difference is decreased from 20.7% to 3.3% by the above strategy. The presented method will have a broad application prospect in the printed circuit board manufacturing field. [ABSTRACT FROM AUTHOR]

The paper present the key technical details of a multifocal near-eye display concept. Along with an overview of the basic architecture, a particular implementation that utilises a digital light processing (DLP®) based spatial light modulator as the image source is provided in the study. The investigated approach involves the utilisation of a small-scale volumetric screen formed by a stack of fast-switching optical diffuser elements based on liquid crystal technology. The volumetric screen is illuminated by a rear image projector. To make the whole system functional and small, the challenge lies within the development of integrated control board for the projection modules as well as the synchronization of the DLP® projector image output to the optical diffuser element switching-cycle. The main difficulty of the development process is accounting for the peculiarities of in-house developed diffuser elements and the off-the-shelf DLP®, which is the main focus of this paper. There is no direct control over the full set of DLP® operational parameters, an indirect method for adjusting frame dead time is proposed, showing that an increase in dead time close to 0.3 ms (from 0.3 ms to 0.6 ms in the particular setup) can be achieved without significantly sacrificing image colour depth or quality. Tuneable dead time mitigates the limitations set by the non-instantaneous switching of liquid crystal diffuser elements as longer dead times allow for the removal of image bleeding between frames. [ABSTRACT FROM AUTHOR]

In this paper, a calculation method of color amplitude‐only computer‐generated hologram (CGH) that can suppress speckle noise is proposed. Firstly, the amplitude information of the red, green and blue channels of the object is extracted. Secondly, to reduce the speckle noise, the convolution result of the amplitude information with a constrained random phase is used as the complex amplitude distribution of the object. Then, the multi‐frame amplitude‐only CGHs for each color channel of the object are generated by using the modified double‐step Fresnel diffraction algorithm. Finally, the digital micromirror device is used to refresh the multi‐frame amplitude‐only CGHs, and the speckle noise is suppressed by using the time‐averaging method. The validity of the computational method is verified. [ABSTRACT FROM AUTHOR]

Technologies of independent amplitude-phase modulation of the wavefront at the output plane of optical systems with spatial filtering are effective in solving a wide range of problems. In this work, we present the results of our experimental study of a numerical displacement of the target wavefront formation plane. We numerically and experimentally show the 1-cm displacement of target wavefront formation plane when using independent amplitude-phase modulation with a digital micromirror device. The wavefronts generated are reconstructed from intensity distributions recorded with a common-path holographic detection system, which is based on geometric phase lens and polarization camera. An increase in quantization levels is shown to be accompanied by a slight deterioration in the spatial resolution of the phase distribution. [ABSTRACT FROM AUTHOR]

• A deep learning-driven digital inverse lithography technology (DDILT) for DMD lithography is proposed. • DDILT operates at a speed advantage of at least three orders of magnitude compared to current methods. • A resist pattern with consistent line width and spacing can be produced by the inverse design of layouts. Digital micromirror device (DMD)-based maskless projection lithography has gained significant attention for its maskless, flexible, and cost-effective characteristics. However, when dealing with target layouts smaller than the wavelength scale, optical proximity effects (OPE) pose a significant challenge in achieving precise resist patterns that closely match the intended layout. To address this issue, we introduce an innovative technique called deep learning-driven digital inverse lithography technology (DDILT). This method optimizes the DMD modulation coefficient to implement optical proximity correction (OPC), significantly improving the printability of target layouts. DDILT allows for reverse engineering target layouts that do not align with the DMD pixel grid, effectively overcoming the limitations imposed by DMD pixel size. Notably, DDILT operates at a speed advantage of at least three orders of magnitude compared to alternative methods. In the case of binary amplitude modulation, it reduces edge distance error (EDE) to just 35% of the original value, providing a rapid and efficient solution for addressing large-scale layout challenges. [ABSTRACT FROM AUTHOR]

A digital micromirror device (DMD) is a programmable pixelated instrument that uses an array of tiny individually switchable mirrors as a rapid spatial light modulator. In this work, we propose a method to determine the smallest size of the input aperture that the DMD can render appropriately. We test this with a DMD with an unusual diamond pixel configuration. We capture the diffraction of a vortex beam by triangular apertures of different sizes in the DMD. We can set the limit if the diffraction patterns have distinct lobes and that they follow the similarity and scaling properties of Fourier transforms of 2D images. Otherwise, the device did not render the aperture correctly. With our particular setup, R = 48 pixels is the size of the smallest triangular aperture that the DMD can render properly. Our result is important especially when using the DMD as a programmable hologram, aperture, or as an imaging device. • A digital micromirror device can act as a programmable aperture but has limits. • We assess a DMD's rendering limit using vortex diffraction and Fourier transform. • The diffraction has distinct lobes when the DMD renders the aperture correctly. • The diffraction obeys Fourier transform scaling properties in proper DMD rendering. • Our work offers a protocol to analyze the limit of other pixelated devices. [ABSTRACT FROM AUTHOR]

This paper provides an in-depth exploration of holographic methodologies, focusing particularly on digital holography facilitated by Digital Micromirror Devices (DMD). We thoroughly examine the theoretical foundations of holographic capture and reconstruction, emphasizing the role of DMDs in these processes. The study covers the principles of diffraction that govern the interaction between light waves and DMDs, alongside a detailed look at the structure, operating principles, and holography-relevant properties of DMDs. We discuss various approaches to creating holographic displays, addressing the inherent challenges and proposing potential solutions. The paper further explores computational strategies for crafting holograms for 3D displays using DMDs and examines multiple advanced techniques for holographic image reconstruction. Our findings highlight the distinctive advantages of DMDs in holography, such as their fast switching speeds, increased angular separation between reconstructed and incident beams, and finer mirror pitch, all contributing to superior hologram quality. We conclude that DMD-based systems hold significant promise for advancing the field of holographic displays. • Examines digital holography with Digital Micromirror Devices (DMD) and explores theoretical foundations. • Explores diffraction principles in light-DMD interaction. • Explores computational strategies for 3D hologram crafting with DMDs. • Explores advanced holographic techniques with DMDs. [ABSTRACT FROM AUTHOR]

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The selective generation of laser transverse modes by gain regulation with a digital micromirror device (DMD) is presented in this letter. The gain regulation in laser medium is adjusted by the switch of the patterns loaded on DMD. Structured pump beam patterns can be obtained after the reflection of the loaded patterns on DMD, and then it’s defocused into a microchip laser medium by a short focal lens, so that the pump patterns can be transferred to the gain medium to regulate the gain distribution. Corresponding structured laser beams can be generated by this laser system. The laser beam pattern can be regulated easily and quickly, by switching the loaded patterns on DMD. Through this method, we show a simple and flexible laser system to generate on-demand laser beam patterns. [ABSTRACT FROM AUTHOR]

This paper presents a portable and affordable prototype using a Digital Micro-mirror Device (DMD) based Near-Infrared Spectrometer and an improved diffuse reflectance illumination module (DRIM). The improved DRIM produced optical geometry parameters such as 3.5mm standoff distance (SD), 2mm depth of overlap illumination area (DOIR), and 4mm sample active illumination area (SAIA). It enables the single and multi-point scans to determine the crude content of various food quality parameters and homogeneity by averaging spatial inhomogeneities of raw material and heterogeneous sample mixtures placed at a standoff distance. The prototype outperformed the current portable NIRS by a factor of 2–3 in terms of optical throughput, signal-to-noise ratio, and baseline. The prototype’s repeatability was determined by assessing pure samples such as chalk powder, red chili powder, wheat, and groundnuts using scattering correction techniques and was computed

Fast reconstruction of holographic and diffractive optical elements (DOE) can be implemented by binary digital micromirror devices (DMD). Since micromirrors of the DMD have two positions, the synthesized DOEs must be binary. This work studies the possibility of improving the method of synthesis of amplitude binary inline Fresnel holograms in divergent beams. The method consists of the modified Gerchberg–Saxton algorithm, Otsu binarization and direct search with random trajectory technique. To achieve a better quality of reconstruction, various binarization methods were compared. We performed numerical and optical experiments using the DMD. Holograms of halftone image with size up to 1024 × 1024 pixels were synthesized. It was determined that local and several global threshold methods provide the best quality. Compared to the Otsu binarization used in the original method of the synthesis, the reconstruction quality (MSE and SSIM values) is improved by 46% and the diffraction efficiency is increased by 27%.

Localized actuation is an important goal of nanotechnology broadly impacting applications such as programmable materials, soft robotics, and nanolithography. Despite significant recent advances, actuation with high temporal and spatial resolution remains challenging to achieve. Herein, we demonstrate strongly localized photoactuation of polymer pens made of polydimethylsiloxane (PDMS) and surface-functionalized short carbon nanotubes based on a fundamental understanding of the nanocomposite chemistry and device innovations in directing intense light with digital micromirrors to microscale domains. We show that local illumination can drive a small group of pens (3 × 3 over 170 μm × 170 μm) within a massively two-dimensional array to attain an out-of-plane motion by more than 7 μm for active molecular printing. The observed effect marks a striking three-order-of-magnitude improvement over the state of the art and suggests new opportunities for active actuation.

A full-field chromatic confocal microscopy (CCM) using a multispectral sensor was developed for quasi-one-shot microscopic 3D surface measurement. An innovative optical configuration employs a digital micromirror device (DMD) and a multispectral sensor is used to realize CCM with full-field area scanning. In the optical design, an area-scan type chromatic dispersive objective is specially designed to achieve measuring specification. Based on a self-developed chromatic dispersive objective, the FOV for one shot measurement can be reached to 1.8×1.3 mm2 which is immersive to microscopic profilometry. The spectral image captured by the multispectral sensor at each pinhole position has a unique spectrum pattern corresponding to its conjugate measured depth. A normalized cross-correlation (NCC) algorithm is developed to establish a spectrum-depth response curve with its corresponding spectrum pattern sets for accurate reconstruction of the tested 3D surface profile. With real test on standard targets, the measurement repeatability for a single surface depth is less than 0.6 μm.

Significance: Cerebral blood flow (CBF) imaging is crucial for diagnosing cerebrovascular diseases. However, existing large neuroimaging techniques with high cost, low sampling rate, and poor mobility make them unsuitable for continuous and longitudinal CBF monitoring at the bedside., Aim: This study aimed to develop a low-cost, portable, programmable scanning diffuse speckle contrast imaging (PS-DSCI) technology for fast, high-density, and depth-sensitive imaging of CBF in rodents., Approach: The PS-DSCI employed a programmable digital micromirror device (DMD) for remote line-shape laser (785 nm) scanning on tissue surface and synchronized a 2D camera for capturing boundary diffuse laser speckle contrasts. New algorithms were developed to address deformations of line-shape scanning, thus minimizing CBF reconstruction artifacts. The PS-DSCI was examined in head-simulating phantoms and adult mice., Results: The PS-DSCI enables resolving Intralipid particle flow contrasts at different tissue depths. In vivo experiments in adult mice demonstrated the capability of PS-DSCI to image global/regional CBF variations induced by 8% CO 2 inhalation and transient carotid artery ligations., Conclusions: Compared to conventional point scanning, the line scanning in PS-DSCI significantly increases spatiotemporal resolution. The high sampling rate of PS-DSCI is crucial for capturing rapid CBF changes while high spatial resolution is important for visualizing brain vasculature.

We present a method for spatial frequency domain data acquisition utilizing a multifrequency synthesis and extraction (MSE) method and binary square wave projection patterns. By illuminating a sample with square wave patterns, multiple spatial frequency components are simultaneously attenuated and can be extracted to determine optical property and depth information. Additionally, binary patterns are projected faster than sinusoids typically used in spatial frequency domain imaging (SFDI), allowing for short (millisecond or less) camera exposure times, and data acquisition speeds an order of magnitude or more greater than conventional SFDI. In cases where sensitivity to superficial layers or scattering is important, the fundamental component from higher frequency square wave patterns can be used. When probing deeper layers, the fundamental and harmonic components from lower frequency square wave patterns can be used. We compared optical property and depth penetration results extracted using square waves to those obtained using sinusoidal patterns on an in vivo human forearm and absorbing tube phantom, respectively. Absorption and reduced scattering coefficient values agree with conventional SFDI to within 1% using both high frequency (fundamental) and low frequency (fundamental and harmonic) spatial frequencies. Depth penetration reflectance values also agree to within 1% of conventional SFDI.

In a lidar system, replacing moving components with solid-state devices is highly anticipated to make a reliable and compact lidar system, provided that a substantially large beam area with a large angular extent as well as high angular resolution is assured for the lidar transmitter and receiver. A new quasi-solid-state lidar optical architecture employs a transmitter with a two-dimensional MEMS mirror for fine beam steering at a fraction of the degree of the angular resolution and is combined with a digital micromirror device for wide FOV scanning over 37 degree while sustaining a large aperture area of 140 mm squared. In the receiver, a second digital micromirror device is synchronized to the transmitter DMD, which enables a large FOV receiver. An angular resolution of 0.57°(H) by 0.23° (V) was achieved with 0.588 fps for scanning 1344 points within the field of view.

Holographic projection is a simple projection as it enlarges or reduces reconstructed images without using a zoom lens. However, one major problem associated with this projection is the deterioration of image quality as the reconstructed image enlarges. In this paper, we propose a time-division holographic projection, in which the original image is divided into blocks and the holograms of each block are calculated. Using a digital micromirror device (DMD), the holograms were projected at high speed to obtain the entire reconstructed image. However, the holograms on the DMD need to be binarized, thereby causing uneven brightness between the divided blocks. We correct this by controlling the displaying time of each hologram. Additionally, combining both the proposed and noise reduction methods, the image quality of the reconstructed image was improved. Results from the simulation and optical reconstructions show we obtained a full-color reconstruction image with reduced noise and uneven brightness. [ABSTRACT FROM AUTHOR]

Digital micromirror devices (DMDs) are spatial light modulators that employ the electro-mechanical movement of miniaturized mirrors to steer and thus modulate the light reflected off a mirror array. Their wide availability, low cost and high speed make them a popular choice both in consumer electronics such as video projectors, and scientific applications such as microscopy. High-end fluorescence microscopy systems typically employ laser light sources, which by their nature provide coherent excitation light. In super-resolution microscopy applications that use light modulation, most notably structured illumination microscopy (SIM), the coherent nature of the excitation light becomes a requirement to achieve optimal interference pattern contrast. The universal combination of DMDs and coherent light sources, especially when working with multiple different wavelengths, is unfortunately not straight forward. The substructure of the tilted micromirror array gives rise to a blazed grating, which has to be understood and which must be taken into account when designing a DMD-based illumination system. Here, we present a set of simulation frameworks that explore the use of DMDs in conjunction with coherent light sources, motivated by their application in SIM, but which are generalizable to other light patterning applications. This framework provides all the tools to explore and compute DMD-based diffraction effects and to simulate possible system alignment configurations computationally, which simplifies the system design process and provides guidance for setting up DMD-based microscopes. This article is part of the Theo Murphy meeting 'Super-resolution structured illumination microscopy (part 1)'. [ABSTRACT FROM AUTHOR]

• A structured light generation scheme using the anti-blaze condition (ABC) of a digital micromirror device (DMD) is proposed. • Since the ABC does not produce a DC component, various structured lights can be generated using a single iris diaphragm. • A series of DMD patterns with various orientation angles are introduced and experimentally verified for the ABC. • The ABC of a DMD can be used in many structured light-based applications. Generating high-frequency sinusoidal intensity patterns with different orientations, periods, and phases is crucial in many optical measurement systems. As the required measurement resolution of an optical metrology system is increased, interference-based structured light generation with a coherent light source is preferred over a projection-based method with an incoherent light source. We propose a powerful high-frequency intensity pattern generation scheme using the anti-blaze condition (ABC) of a digital micromirror device (DMD). Unlike conventional methods using the blaze condition of a DMD, our proposed method is intrinsically free from a DC component, which can circumvent the requirements of matched spatial filters and sophisticated alignments. We have experimentally verified the feasibility of our proposed method by proposing a series of DMD patterns that can generate various high-frequency two-beam interference patterns. [ABSTRACT FROM AUTHOR]

For the first time, demonstrated is an extreme linear Dynamic Range (DR) Pixels of Interest (POI) [i.e., Coded Access Optical Sensor (CAOS)] Digital Single Lens Reflex (DSLR) camera design that engages three different types of photosensors within one optomechanical assembly to smartly identify POI across a one billion to one light irradiance range. A pixelated CMOS sensor provides a limited DR and linearity image by engaging a moveable mirror placed between the Digital Micromirror Device (DMD) and the frontend imaging lens. Next using DMD control, non-POI light is directed away from the chosen point photodetector (PD) engaged for high DR POI image recovery, giving the PD an improved use of quantum well capacity. For brighter POI, a solid state photodiode point PD with an electronic gain controlled amplifier is engaged while for weaker light POI, a photomultiplier tube (PMT) with variable optical gain is deployed. POI imaging is achieved using time-frequency CAOS modes via DMD control and time-frequency correlation and spectral digital signal processing. A 123.4 dB linear DR POI recovery is achieved for a custom incoherent white light 36-patch target while a record 177 dB linear DR recovery is demonstrated for a single patch 633 nm laser target. For the first time, a 1023 POI frame, real-time 48 frames/s update rate CAOS imaging is demonstrated for tracking a changing focal spot moving laser target.

Spectral reconstruction method based on narrow-band measurements has been demonstrated to achieve ultrafast spectroscopic imaging with high spatial and spectral resolution, in which multiple narrow-band images are collected by using several specific filters. Although commercially available filters can be employed in such method, filters with complex transmittance that are difficult to be fabricated typically show significant improvement in spectral reconstruction accuracy. In this study, a two dimensional programmable optical filter based on digital micromirror device (DMD) is proposed, in which its transmittance spectrum can be arbitrarily and quickly switched to realize complex transmittance. Furthermore, its flexible transmittance enables directly hardware-based spectral data post-processing, which can perform data acquisition and analysis simultaneously. Those have been evaluated by the diffuse reflectance spectra from normal and occluded skin flaps, as well as Raman spectra from live, apoptosis and necrosis leukemia cells. Our simulation results show that much higher spectral reconstruction accuracies can be achieved by the optimized filters with complex transmittance. Furthermore, the classification accuracy by using the proposed method is comparable to those achieved by conventional numerical methods. Therefore, based on the proposed programmable optical filter, fast spectroscopic imaging with high spatial and spectral resolution can be achieved for observing fast changing phenomena and even real-time target identification.

Invisible-light communication between a projector and multiple devices on the projection plane enables human-computer interaction applications such as movable displays and pointing devices. In this paper, we propose a pixel-level infrared light communication (PILC) projector that can project rich, invisible position-dependent information on high-contrast, full-color visible images. Although previous methods for such communication sacrificed the image quality, the amount of information, or other features, our method meets all the requirements by adding an infrared light source to a full-color DLP projector. This system alternately projects visible images and invisible data sequences with visible and infrared light, respectively. As proof of concept, we built a functional prototype and confirmed that its image contrast is more than 60 times that of a previous method while maintaining pixel-level position accuracy. In addition, we investigated flicker-perception rates in response to different amounts of embedded information and discovered that we could send rich information (up to approximately 2 kbps) with imperceptible flicker. Finally, we built a tabletop application with the proposed system, in which users can simultaneously see both an aerial photograph and a map through movable displays.

A method is proposed for the synthesis of self-focusing amplitude diffractive optical elements (DOEs) without a carrier spatial frequency for operation in diverging beams and forming a single focused diffraction order, which can occupy the entire region of the DOE image being reconstructed due to the absence of the need for spatial separation of orders. The synthesis takes place in two stages. The first is carried out by an iterative algorithm similar to the Gerchberg–Saxton algorithm, with the differences that the synthesized DOE is amplitude rather than phase, and the incident wavefront is diverging spherical. Next, the direct search with a random trajectory method is applied. As a result, for a binary amplitude DOE, it was possible to achieve synthesis error values of 6% and a diffraction efficiency of 6%. The results of the experimental implementation of DOE using a digital micromirror device are presented. [ABSTRACT FROM AUTHOR]

Recently, digital photography has become an efficient and economic method to assist dermatologists in monitoring skin characteristics. Although this technology has advanced a great deal in resolution and costs, conventional digital cameras continue to only provide qualitative recording of color information. To address this issue, we are developing a compact, quantitative skin imaging camera by employing spatial frequency domain imaging (SFDI), a non-contact approach for determining tissue optical properties over a wide field-of-view. SFDI uses knowledge of optical properties at multiple wavelengths to recover concentrations of tissue constituents such as oxy/deoxy-hemoglobin, water, and melanin. This method has been well researched and presented in laboratory and research settings. The next step in the development of SFDI systems is to make typical systems compact and cheaper using commercial components. We present our findings by performing a component-by-component analysis of key SFDI system components including light sources, projectors, and cameras. © 2013 Copyright SPIE.

Obtaining molecular information deeper within optically turbid samples is valuable in many applications. However, in many cases this is challenging, in particular when the sample elicits strong laser-induced fluorescence emission. Here, we investigated the use of time-gated and micro-spatially offset Raman spectroscopy (micro-SORS) based on spectral multiplexing detection to obtain sub-surface molecular analysis and imaging for both fluorescing and non-fluorescing samples. The multiplexed spectral detection achieved with a digital micromirror device (DMD) allowed fast acquisition of the time-gated signals to enable three-dimensional Raman mapping (raster scanning in the lateral x,y plane and using time-of-flight calibration for the axial z -direction). Sub-millimeter resolution molecular depth mapping was achieved with dwell times on the order of seconds per pixel. To suppress fluorescence backgrounds and enhance Raman bands, time-gated Raman spectroscopy was combined with micro-SORS to recover Raman signals of red pigments placed behind a layer of optically turbid material. Using a defocusing micro-SORS approach, both fluorescence and Raman signals from the surface layers were further suppressed, which enhanced the Raman signals from the deeper sublayers containing the pigment. These results demonstrate that time-gated Raman spectroscopy based on spectral multiplexed detection, and in combination with micro-SORS, is a powerful technique for sub-surface molecular analysis and imaging, which may find practical applications in medical imaging, cultural heritage, forensics, and industry. [ABSTRACT FROM AUTHOR]

Confocal endoscopy has been widely used to obtain fine optically sectioned images. However, confocal endomicroscopic images are formed by point‐by‐point scanning in both lateral and axial directions, which results in long image acquisition time. Here, an endomicroscope with telecentric configuration is presented to achieve nonmechanical and rapid axial scanning for volumetric fluorescence imaging. In our system, optical sectioning in wide‐field fashion is obtained through HiLo imaging with a digital micromirror device. Axial scanning, without mechanical moving parts, is conducted by digital focus adjustment using an electrically tunable lens, offering constant magnification and contrast. We demonstrate imaging performance of our system with optically sectioned images using fluorescently labeled beads, as well as ex vivo mice cardiac tissue samples. Our system provides multiple advantages, in terms of improved scanning range, and reduced image acquisition time, which shows great potentials for three‐dimensional biopsies of volumetric biological samples. [ABSTRACT FROM AUTHOR]

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). [ABSTRACT FROM AUTHOR]

For the first time, a CAOS (i.e., Coded Access Optical Sensor) spectrometer is demonstrated. The design implemented uses a reflective diffraction grating and a time-frequency CAOS mode operations Digital Micromirror Device (DMD) in combination with a large area point photo-detector to enable highly programmable linear High Dynamic Range (HDR) spectrometry. Experiments are conducted with a 2850 K color temperature light bulb source and visible band color bandpass and high-pass filters as well as neutral density (ND) attenuation filters. A ~369 nm to ~715 nm input light source spectrum is measured with a designed ~1 nm spectral resolution. Using the optical filters and different CAOS modes, namely, Code Division Multiple Access (CDMA), Frequency Modulation (FM)-CDMA and FM-Time Division Multiple Access (TDMA) modes, measured are improving spectrometer linear dynamic ranges of 28 dB, 50 dB, and 96.2 dB, respectively. Applications for the linear HDR CAOS spectrometer includes materials inspection in biomedicine, foods, forensics, and pharmaceuticals. [ABSTRACT FROM AUTHOR]

High-speed optical reconstruction of 3D-scenes can be achieved using digital holography with binary digital micromirror devices (DMD) or a ferroelectric spatial light modulator (fSLM). There are many algorithms for binarizing digital holograms. The most common are methods based on global and local thresholding and error diffusion techniques. In addition, hologram binarization is used in optical encryption, data compression, beam shaping, 3D-displays, nanofabrication, materials characterization, etc. This paper proposes an adaptive binarization method based on a combination of local threshold processing, hologram division into blocks, and error diffusion procedure (the LDE method). The method is applied for binarization of optically recorded and computer-generated digital holograms of flat objects and three-dimensional scenes. The quality of reconstructed images was compared with different methods of error diffusion and thresholding. Image reconstruction quality was up to 22% higher by various metrics than that one for standard binarization methods. The optical hologram reconstruction using DMD confirms the results of the numerical simulations.

Collaboration between computer graphics and multiple robots has attracted increasing attention in several fields. To enhance the seamless connection between them, the system should be able to accurately determine the position and state of the robots and to control them easily and instantly. However, realizing a responsive control system for a large number of mobile robots without complicated settings while avoiding the system load problem is not trivial. We propose a novel system, called “Phygital Field,” for the localization and control of multiple mobile robots. Utilizing pixel-level visible light communication technology, our system can project two types of information in the same location: visible images for humans and data patterns for mobile robots. The system uses coded light superimposed onto a visual image and projected onto the robots. The robots localize their position by receiving and decoding the projected light and can follow a target using the coded velocity vector field. Localization and control information can be independently conveyed in each pixel, and we can change this information over time. The system only requires a projector to control the robot swarm; thus, it can be used on any projection surface. We experimentally assess the localization accuracy of our system for both stationary and moving robots. To further illustrate the utility of our proposed system, we demonstrate the control of multiple mobile robots in spatially and temporally varying vector fields. We also propose prototype applications that can provide users with novel content from collaboration between computer graphics and robot swarm.