Μm Side Research Articles

Mechanics of Fluid-Filled Interstitial Gaps. II. Gap Characteristics in Xenopus Embryonic Ectoderm

The ectoderm of the Xenopus embryo is permeated by a network of channels that appear in histological sections as interstitial gaps. We characterized this interstitial space by measuring gap sizes, angles formed between adjacent cells, and curvatures of cell surfaces at gaps. From these parameters, and from surface-tension values measured previously, we estimated the values of critical mechanical variables that determine gap sizes and shapes in the ectoderm, using a general model of interstitial gap mechanics. We concluded that gaps of 1–4 μm side length can be formed by the insertion of extracellular matrix fluid at three-cell junctions such that cell adhesion is locally disrupted and a tension difference between cell-cell contacts and the free cell surface at gaps of 0.003 mJ/m2 is generated. Furthermore, a cell hydrostatic pressure of 16.8 ± 1.7 Pa and an interstitial pressure of 3.9 ± 3.6 Pa, relative to the central blastocoel cavity of the embryo, was found to be consistent with the observed gap size and shape distribution. Reduction of cell adhesion by the knockdown of C-cadherin increased gap volume while leaving intracellular and interstitial pressures essentially unchanged. In both normal and adhesion-reduced ectoderm, cortical tension of the free cell surfaces at gaps does not return to the high values characteristic of the free surface of the whole tissue.

Development of an integrated Monte Carlo model for glioblastoma multiforme treated with boron neutron capture therapy

Glioblastomas (GBM) are notorious for their high fatality rate. Boron Neutron Capture Therapy (BNCT) being a biochemically targeted type of radiotherapy is a potent modality for GBM. In the current work, a BNCT treatment modelling framework for GBM was developed. Optimal Clinical Target Volume (CTV) margins for GBM-BNCT and the BNCT efficacy have been investigated. The model integrated a cell-based dosimetry model, an in-house-developed epithermal neutron beam model and previously-developed Microscopic Extension Probability (MEP) model. The system was defined as a cubic ICRP-brain phantom divided into 20 μm side voxels. The corresponding 10B concentrations in GBM and normal brain cells were applied. The in-silico model was irradiated with the epithermal neutron beam using 2 and 2.5 cm CTV margins. Results from the cell-based dosimetry and the MEP models were combined to calculate GBM cell survival fractions (SF) post BNCT and compared to x-ray radiotherapy (XRT) SFs. Compared to XRT, the SF within the beam decreased by five orders of magnitudes and the total SF was reduced three times following BNCT. CTV extension by 0.5 cm reduced the SF by additional (53.8 ± 0.3)%. In conclusion, BNCT results in a more efficient cell kill. The extension of the CTV margin, however, may not increase the treatment outcome significantly.

Friction Reduction of Chrome-Coated Surface with Micro-Dimple Arrays Generated by Electrochemical Micromachining

Surface coating and surface texture play a significant role in enhancing the tribological properties of mechanical components. In this study, to further improve the tribological properties of a chrome-coated surface, arrays of circular- and square-shaped micro-dimples were generated on chrome-coated surfaces via electrochemical machining. Through-mask electrochemical micromachining (TMEMM) is a popular electrochemical micromachining method for generating micro-dimple arrays. However, photolithography is a necessary process in conventional TMEMM before electrochemical micromachining, which is time-consuming and expensive when used in mass production. A reusable polydimethylsiloxane mask was introduced to prepare the micro-dimples. Circular micro-dimples of 120 μm diameter and square micro-dimples of 106 μm side length were fabricated on a chrome-coated surface. The results of friction tests indicated that at a load of 220 N, 10 μm deep micro-dimples reduced the coefficient of friction (CoF) significantly compared to an untextured surface. At a load of 320 and 420 N, the CoF continually decreased when the depth of the micro-dimples was increased from 0 to 20 μm. In addition, the results showed that, compared to circular micro-dimples, square micro-dimples contributed to a higher friction reduction ratio under the same conditions. The best friction reduction ratio was found for square dimples with a depth of 20 μm.

Superhydrophobic ZnAl double hydroxide nanostructures and ZnO films on Al and glass substrates

Superhydrophobic nanostructured ZnAl: layered double hydroxides (LDHs) and ZnO films have been fabricated on Al and glass substrates, respectively, by a simple and cost effective chemical bath deposition technique. Randomly oriented hexagonal patterned of ZnAl: LDHs thin nanoplates are clearly observed on Al-substrate in the scanning electron microscopic images. The average size of these hexagonal plates is ∼4 μm side and ∼30 nm of thickness. While on the glass substrate, a oriented hexagonal patterned ZnO nanorods (height ∼5 μm and 1 μm diameter) are observed and each rod is further decorated throughout the top few nanometers with several nanosteps. At the top of the nanorod, a perfectly hexagonal patterned ZnO surface with ∼250 nm sides is observed. The tendency to form hexagonal morphological features is due to the hexagonal crystal structure of ZnO confirmed from X-ray diffraction patterns and transmission electron microscopy image. The ZnAl: LDHs and/or ZnO coated substrates have been passivated by using stearic acid (SA) molecules. Infrared spectra of passivated ZnAl: LDHs coated substrates confirm the presence of SA. X-ray diffraction pattern also corroborates the results of infrared spectrum. The contact angle of the as prepared samples is zero. The superhydrophobicity is achieved by observing contact angle of ∼161° with a hysteresis of ∼4° for Al-substrate. On the glass substrate, a higher contact angle of ∼168° with a lower hysteresis of ∼3° is observed. A lower surface roughness of ∼4.93 μm is measured on ZnAl: LDHs surface layer on the Al substrate as compare to a higher surface roughness of 6.87 μm measured on ZnO layer on glass substrate. The superhydrophobicity of passivated nanostructured films on two different substrates is observed due to high surface roughness and low surface energy.

Developments in micro- and nano-defects detection using bacterial cells

This paper describes improvements to the Nondestructive Testing (NDT) technique recently proposed, based on the use of bacterial cell suspensions to identify micro- and nano-surface defects. New bacterial strains were used with magnetic fields to improve bacteria mobility. Different materials and defect morphologies were tested, including nanoindentation defects, micro-powder injection moulding components and micro-laser welding. Nanoindentations with 0.6µm depth and 5.3µm side length were successfully detected. Bacterial cells allow identifying different topographic attributes of the surfaces, such as roughness. Cracks of about 0.5µm wide and 10µm depth in a reference test block Type 1 were successfully detected.

Investigating inhomogeneous electronic properties of radial junction solar cells using correlative microscopy

Solar cells with radial junctions based on silicon nanowires were investigated using correlative microscopy in order to determine the nature and origin of previously reported inhomogeneity of their electronic properties. For correlating various microscopy techniques, we have prepared sets of three Vickers type nanoindents arranged in a right triangle with 20 µm sides as marks of local frame of reference. Due to the shape of the indents (squares with 4 µm sides and clear diagonals) the position of the marks can be located with high precision by various microscopes. This makes it possible to correlate the results from scanning electron microscopy, Kelvin probe force microscopy and conductive atomic force microscopy techniques on the same place of the sample, with a precision down to individual nanowires, obtaining new information about the electronic inhomogeneity. Using the conductive AFM we analyzed the growth process of silicon nanowires step by step in order to find possible origins of the local (photo)current variations.

Three Dimensional, High Resolution MPL Generation for Thermal and Mass Transport Modeling of PEM Fuel Cells

The microporous layer (MPL) of the polymer electrolyte membrane (PEM) fuel cell has been shown to significantly improve the performance of the fuel cell1. However, there remains a lack of conclusive evidence for the transport processes through the MPL. The nano-scale pore sizes limit the probing capabilities of experimental and visualization studies2,3. Based on information from previous characterization studies done at a relatively low resolution, a stochastically generated MPL model has been built that closely represents the structural properties of the MPL coating of SGL 25BC, which is a commercially available gas diffusion layer (GDL) used in automotive applications. This model is the first step for designing MPLs and studying their thermal and mass transport properties. In this work, the MPLs have been generated with a particle diameter of 60 nm and a filling radius of 12 nm, which statistically represents the MPL of SGL 25BC2. Additional MPL structures have also been generated with varying particle diameters, filling radii, and particle overlaps to better understand the structural properties impact on thermal and mass transport. The filling radius represents the addition of a binding material to the MPL, and polytetrafluoroethylene (PTFE) is commonly used in this manufacturing process. PTFE is uniformly distributed throughout the MPL structure, as shown by George et al.4 and assumed by El Hannach et al.5. The MPL structure being generated treats the carbon particles and the PTFE as separate materials. This allows for accurate simulation of heat transfer through the structure, which is dependent on the thermal properties of the solid. Figure 1 shows a 1.5 µm x 1.5 µm x 1.5 µm domain of the MPL which has been generated at a voxel resolution of 5 nm/voxel. Higher resolution structures (at 1 nm/voxel) have also been generated. However, the computational cost of the higher resolution is not justified by the improvement in the results. The resulting structures have been validated by calculating the diffusivity of oxygen through the pores. The diffusivity calculations have been done using the pore network modeling technique, implemented through our open source pore network model, OpenPNM (www.openpnm.org). The high resolution of the structure allows for studying the particle to particle contact region, which is extremely critical in heat transfer studies. This model has been used to study the effect of particle size, binder ratio, and structure on the heat and mass transport through the MPL. This work will provide valuable data for improved performance modeling of the fuel cell towards the goal of reducing the experimental cost and the iteration time of designing new MPLs for advanced heat and mass transport management. Figure 1: 1.5 µm side length domain of MPL generated using the scheme mentioned in this work.

Evaluation of current clinical target volume definitions for glioblastoma using cell-based dosimetry stochastic methods.

Determination of an optimal clinical target volume (CTV) is complex and remains uncertain. The aim of this study was to develop a glioblastoma multiforme (GBM) model to be used for evaluation of current CTV practices for external radiotherapy. The GBM model was structured as follows: (1) a Geant4 cellular model was developed to calculate the absorbed dose in individual cells represented by cubic voxels of 20 μm sides. The system was irradiated with opposing 6 MV X-ray beams. The beams encompassed planning target volumes corresponding to 2.0- and 2.5-cm CTV margins; (2) microscopic extension probability (MEP) models were developed using MATLAB(®) 2012a (MathWorks(®), Natick, MA), based on clinical studies reporting on GBM clonogenic spread; (3) the cellular dose distribution was convolved with the MEP models to evaluate cellular survival fractions (SFs) for both CTV margins. A CTV margin of 2.5 cm, compared to a 2.0-cm CTV margin, resulted in a reduced total SF from 12.9% ± 0.9% to 3.6% ± 0.2%, 5.5% ± 0.4% to 1.2% ± 0.1% and 11.1% ± 0.7% to 3.0% ± 0.2% for circular, elliptical and irregular MEP distributions, respectively. A Monte Carlo model was developed to quantitatively evaluate the impact of GBM CTV margins on total and penumbral SF. The results suggest that the reduction in total SF ranges from 3.5 to 5, when the CTV is extended by 0.5 cm. The model provides a quantitative tool for evaluation of different CTV margins in terms of cell kill efficacy. Cellular platform of the tool allows future incorporation of cellular properties of GBM.

Sub-micron gap in-plane micromechanical resonators based on low-temperature amorphous silicon thin-films on glass substrates

In this work, high-frequency bulk mode resonators made from low stress hydrogenated amorphous silicon (a–Si:H) thin-films are demonstrated. The microelectromechanical structures are fabricated using surface micromachining techniques at a maximum processing temperature of 175 °C on glass substrates. The silicon thin-film based resonators presented here are temperature compatible with post processing on standard CMOS. The resonators are capacitively driven and sensed across 400 nm air gaps. A proof of concept design consisting of a 200 µm side length square has been selectively excited in the Lamé-mode at a characteristic vibration frequency of 13.64 MHz. The quality factor of the resonators is in the 103 range and the motional resistance was measured to be approximately 21.8 MΩ at a DC bias voltage of 40 V.

2.2–2.7 μm side wall corrugated index coupled distributed feedback GaSb based laser diodes

We report on the modeling, growth, processing, characterization and integration in a gas detection setup of side wall corrugated distributed feed-back antimonide diode lasers emitting at 2.28 and 2.67 μm. The laser structures were grown by molecular beam epitaxy on GaSb substrate. Ridge lasers were fabricated from the grown wafers according to the following process: a second order Bragg grating was defined on the sides of the ridges by interferometric lithography, optical lithography and etched in a Cl-based inductively coupled plasma reactor. The devices exhibit a power reaching 40 mW, a side mode suppression ratio better than 28 dB and a tuning range of 3 nm at room temperature. One of these devices was successfully integrated in a tunable diode laser absorption spectroscopy setup, thus demonstrating that they are suitable for gas analysis.

Combinatorial DNA damage pairing model based on X-ray-induced foci predicts the dose and LET dependence of cell death in human breast cells.

In contrast to the classic view of static DNA double-strand breaks (DSBs) being repaired at the site of damage, we hypothesize that DSBs move and merge with each other over large distances (μm). As X-ray dose increases, the probability of having DSB clusters increases as does the probability of misrepair and cell death. Experimental work characterizing the X-ray dose dependence of radiation-induced foci (RIF) in nonmalignant human mammary epithelial cells (MCF10A) is used here to validate a DSB clustering model. We then use the principles of the local effect model (LEM) to predict the yield of DSBs at the submicron level. Two mechanisms for DSB clustering, namely random coalescence of DSBs versus active movement of DSBs into repair domains are compared and tested. Simulations that best predicted both RIF dose dependence and cell survival after X-ray irradiation favored the repair domain hypothesis, suggesting the nucleus is divided into an array of regularly spaced repair domains of ∼1.55 μm sides. Applying the same approach to high-linear energy transfer (LET) ion tracks, we are able to predict experimental RIF/μm along tracks with an overall relative error of 12%, for LET ranging between 30-350 keV/μm and for three different ions. Finally, cell death was predicted by assuming an exponential dependence on the total number of DSBs and of all possible combinations of paired DSBs within each simulated RIF. Relative biological effectiveness (RBE) predictions for cell survival of MCF10A exposed to high-LET showed an LET dependence that matches previous experimental results for similar cell types. Overall, this work suggests that microdosimetric properties of ion tracks at the submicron level are sufficient to explain both RIF data and survival curves for any LET, similarly to the LEM assumption. Conversely, high-LET death mechanism does not have to infer linear-quadratic dose formalism as done in the LEM. In addition, the size of repair domains derived in our model are based on experimental RIF and are three times larger than the hypothetical LEM voxel used to fit survival curves. Our model is therefore an alternative to previous approaches that provides a testable biological mechanism (i.e., RIF). In addition, we propose that DSB pairing will help develop more accurate alternatives to the linear cancer risk model (LNT) currently used for regulating exposure to very low levels of ionizing radiation.

Use of the μPIV technique for an indirect determination of the microchannel cross-section passage geometry

In this work the possible use of the μPIV technique for the experimental determination of the microchannel cross-section geometry has been investigated by means of a blind test in which a series of experimental measurements obtained using glass microchannels having a declared rectangular cross-section with a depth of 100 μm and width of 300 μm and a square microchannel with a 300 μm side have been compared with the direct SEM visualisation of the real cross section of the microchannels. For the (oPIV measurements water is used as working fluid. The laminar fully developed 2D velocity profile has been reconstructed by moving the focal plane of the microscope objective from the bottom to the top of the microchannel. The results shown in this paper demonstrate that the real cross section geometry of the microchannel can be predicted by minimizing the difference between the theoretical and the experimental 2D velocity profiles. When the right passage geometry is determined, the average difference between the theoretical and the experimental velocity is within 4-6%.

A design tool fully adapted to the development of the thin film packaging process used for MEMS devices

MEMS Wafer Level Packaging is required for mass production of MEMS devices: wafer to wafer bonding is usually the current solution, however thin film encapsulation becomes a promising alternative method [1]. Nevertheless, major challenges should be overcome to develop thin film encapsulation, namely the development of a thin cap strong enough to withstand high mold pressures. Consequently, design tools are required to develop successfully thin film encapsulation [2–4]. For that, finite element models (FEM) are commonly used, and this article proposes a generic methodology based on an efficient convergence loop to fit FEM results with experimental data. Our convergence loop guarantees reliable predictive FEM results because our results are double checked with experimental characterizations: we use not only the cap geometry evolution during the process flow, but also the mechanical properties of the cap and especially its stiffness. A study case which shows how to manage the cap deflection during the cap release operation is used to illustrate the relevance of our methodology. To recall [5], the thin film encapsulation requires closed cavities formed above the MEMS devices with surface micromachining techniques: the cavity is formed with a sacrificial layer recovered by a cap. The cap is then perforated by holes to remove the sacrificial layer. Finally, a film is deposited on the cap to seal the cap holes. In practice, the release of the sacrificial layer is one of the most critical operations because the cap can damage the MEMS device due to a buckling effect. Indeed, the residual stresses within the capping layer (compressive residual stresses are usually mandatory) and the geometry of the sacrificial layer have to be tuned in order to control the final shape of the cap. The study case is focused on a test structure with a silicon oxide quadratic plate of 800 μm side length and 3 μm thickness. In practice, the cap geometry has been characterized with a mechanical profilometer; and, a force/displacement curve obtained by nano-indentation technique has been used to extract accurately the mechanical properties of the cap. Then, these experimental data have been used to build our FEM model. The correlation between experimental data and FEM results allows verifying our model because we show that the simulated profile and the simulated stiffness fit successfully with experimental data. The best result has been obtained with a 60MPa compressive residual stress; and, this value is in agreement with experimental measurements. We have used our FEM model to detail the effect of several parameters like the silicon oxide thickness, the residual stresses, the height of the cap edge rolls, or the added value of reinforcement solutions as corrugated membrane or metallic layer. Finally, we conclude that our model is an efficient design tool to optimize the thin film encapsulation. For example, it becomes possible to monitor the buckling effect of the cap by the cavity geometry or the cap material residual stresses.

Patterning of Conducting Polymers Using UV Lithography: The in-Situ Polymerization Approach

We report on the in-situ polymerization of 3T with Cu(ClO4)2 inside several host polymers such as Novolak-based negative-tone photoresist, polystyrene (PS), poly(4-vinylphenol) (P4VP), poly(methyl methacrylate) (PMMA), and poly(4-vinylphenol)-co-(methyl methacrylate) (P4VP-co-MMA) to form an interpenetrating polymer network (IPN). Conducting IPN films in the order of 10–4–150 S/cm are obtained depending on the specific IPN composition. Moreover, the convenience of this synthetic approach has been demonstrated using a commercially available negative-tone photoresist based on Novolak as a host polymer. Novolak photoresist was properly formulated with 3T and Cu(ClO4)2 to preserve as far as possible the negative lithographic characteristics of Novolak-based photoresist and generate conductive micropatterns by means of UV lithography. The CP is in situ synthesized into the Novolak matrix by a postbake after the lithography process (exposure + development). The electrical conductivity of the patterned film is 10–2 S/cm. We accurately patterned three different types of microstructures with different resolutions: interdigitated structures with a width of 100 μm, 200 μm side squares, and a 20 μm wide cross. We believe this synthetic approach is of potential application to modify the conductivity of numerous insulating polymers while preserving their physical and chemical properties.

Mode characterization of sub-micron equilateral triangular microcavity including material’s dispersion effects

We report the study of resonant modes in an equilateral triangular gallium nitride (GaN) microcavity, with the material’s dispersion taken into account. From the polarization-resolved photo-luminescence measurements, we observed the resonance of GaN bandedge emission with the cavity modes to be transverse magnetic-polarization active and characterized with a quality factor as high as ∼1000 in a GaN cavity of 0.75 µm side length. Using a finite difference time domain technique, we showed that these observations can be ascribed to the material’s dispersion effects. The latter can modify the cavity phase-matching condition, reduce the spectral bandwidth of the corresponding resonant modes and enhance the cavity quality factor by a factor more than three.

Mechanical Design and Characterization for MEMS Thin-Film Packaging

In this paper, a thin-film packaging approach is developed. It is meant to provide microelectromechanical systems (MEMS) devices with hermetic encapsulation that is sufficiently strong for transfer molding. A flat slab structure supported by columns is considered as basic geometry for the mechanical model. It takes into account both the plate deflection and the stress at the interface with the columns. To verify the model validity, thin-film packages are fabricated using silicon nitride as material for the capping layer. Both high- and low-temperature processes are used to fabricate the packages. The packages differ for the diameter of the columns (from 2 μm to 28 μm), the distances between columns (from 20 μm to 100 μm), and the capping layer thickness (from 3 μm to 7 μm). The packages are tested at different pressures up to 12.5 MPa (125 bar). Failure points agree well with the mechanical model. The largest package fabricated is a square package of 300 μm side length and with four columns (10 μm diameter) in the middle. It withstands a pressure of 10 MPa with a thin SiN capping layer with a thickness of 6 μm. Moreover, the packages are carried through grinding, dicing, and transfer molding, demonstrating that the presented thin-film encapsulation approach is robust enough for commercial first-level packaging.

Ablation Free Dicing of 4H-SiC Wafers with Feed Rates up to 200 mm/s by Using Thermal Laser Separation

ABSTRACTThis paper presents Thermal Laser Separation (TLS) as a novel dicing technology for silicon carbide (SiC) wafers. Results of this work will play an important role in improving the SiC dicing process regarding throughput and edge quality. TLS process parameters were developed for separating 4H-SiC wafers. Separated SiC dies were analyzed and compared with results produced with current state of the art blade dicing technology. For the first time, fully processed 100 mm 4H-SiC wafers with a thickness of 450 μm, including epi-layer and back side metal layers, could be separated with feed rates up to 200 mm/s. Besides the vastly improved dicing speed, the TLS separation process results in two important features of the separated SiC devices: First, edges are free of chipping and therefore of higher quality than the edges produced by blade dicing. Second, the TLS process is kerf free, which allows for reducing the necessary dicing street width and hence increasing the number of devices per wafer.

Fabrication of a negative PMMA master mold for soft-lithography by MeV ion beam lithography

In this study, poly(methyl methacrylate) (PMMA) was investigated as a negative resist by irradiation with a high-fluence 2 MeV proton beam. The beam from a 1.7 MV Tandetron accelerator at the Plasma and Beam Physics Research Facility (PBP) of Chiang Mai University is shaped by a pair of computer-controlled L-shaped apertures which are used to expose rectangular pattern elements with 1–1000 μm side length. Repeated exposure of rectangular pattern elements allows a complex pattern to be built up. After subsequent development, the negative PMMA microstructure was used as a master mold for casting poly(dimethylsiloxane) (PDMS) following a standard soft-lithography process. The PDMS chip fabricated by this technique was demonstrated to be a microfluidic device.

Performance and Applications of the CdTe- and Si-XPAD3 photon counting 2D detector

The XPAD3 is the third generation of a single photon counting chip developed in collaboration by SOLEIL Synchrotron, the Institut Néel and the Centre de Physique de Particules de Marseille (CPPM). The chip contains 9600 pixels of 130 μm side and a counting electronic chain with an adjustable low level threshold in each pixel. Imaging and detection performance (detective quantum efficiency, modulation transfer function and energy resolution) of the XPAD3 detectors hybridized with Si and CdTe sensors have been evaluated and compared using monochromatic synchrotron X-rays beam. A second version of the chip, optimized for pump-probe experiments, has been realized and successfully tested. Three 7.3 cm x 12.5 cm Si-XPAD3 imagers, composed of 8 silicon modules (7 chips per module) and one 2.1 cm x 3.1 cm CdTe-XPAD3 imager (4 chips) have been constructed and successfully used for synchrotron diffraction experiments and biomedical imaging.

Digital Micro-mirror Device-based broadband optical image sensor for robust imaging applications

To the best of the authors' knowledge, presented for the first time is the design of a robust broadband optical image sensor using a Digital Micro-mirror Device (DMD). Electronic focus control of the imaging lens and full programmability of the spatial sampling aperture shape, size, and location on the DMD plane that mechanically scans the incident incoherent optical irradiance distribution lead to imaging smartness. Dual port single-point photo-detection design provides imaging operation robustness to the global light irradiance variations such as via environmental effects, e.g., moving clouds. As the Texas Instruments (TI) DMD can provide light modulation over 400 nm to 2500 nm wavelengths, visible, Near Infrared (NIR), and Short-Wave Infrared (SWIR) bands can be simultaneously processed to generate three independent band images via three point photo-detectors. A proof-of-concept experiment in the SWIR band at 1580 nm is conducted using an incoherent heart-shaped target that is sampled using the DMD imager set for a 68.4 μm side square moving pinhole. A 60 × 60 pixel image from the proposed imager produces a 0.94 cross-correlation peak when compared to an optically attenuated heart shape image produced by a near 9 μm pixel size phosphor coated Charge Coupled Device (CCD) imager. Using the dual-detection method, robust 633 nm visible light imaging of an Air Force (AF) Chart figure is successfully demonstrated for 3 Hz global light fluctuation. Applications for the proposed imager include optical sensing in the fields of astronomy, defense, medicine, and security.