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Papers by victor bright

Optics Express

Optical sectioning structured illumination microscopy (OS-SIM) provides optical sectioning capabi... more Optical sectioning structured illumination microscopy (OS-SIM) provides optical sectioning capability in wide-field microscopy. The required illumination patterns have traditionally been generated using spatial light modulators (SLM), laser interference patterns, or digital micromirror devices (DMDs) which are too complex to implement in miniscope systems. MicroLEDs have emerged as an alternative light source for patterned illumination due to their extreme brightness capability and small emitter sizes. This paper presents a directly addressable striped microLED microdisplay with 100 rows on a flexible cable (70 cm long) for use as an OS-SIM light source in a benchtop setup. The overall design of the microdisplay is described in detail with luminance-current-voltage characterization. OS-SIM implementation with a benchtop setup shows the optical sectioning capability of the system by imaging within a 500 µm thick fixed brain slice from a transgenic mouse where oligodendrocytes are lab...

DESALINATION AND WATER TREATMENT

Direct monitoring techniques of fouling in membrane-based filtration processes can be implemented... more Direct monitoring techniques of fouling in membrane-based filtration processes can be implemented as part of an effort to reduce the negative effects of membrane fouling. In particular, monitoring techniques with chemical characterization capability are crucial for the formulation of effective fouling prevention and mitigation strategies. In the present work, Raman spectroscopy was applied as an in-situ monitoring technique for calcium carbonate scaling on commercial reverse osmosis membranes. The bench-scale Raman monitoring system allowed for a qualitative chemical assay of the scaled membrane surface at sequential downstream and upstream axial positions. The time evolution of the downstream and upstream calcium carbonate Raman signal was evaluated with respect to computed values of local concentration at the membrane surface, revealing a statistically significant dependence (p < 0.001). The real-time Raman data were bolstered by results of post-mortem analysis (scanning electron microscopy, gravimetric measurements, and laser interferometry). The employed technique was capable of detecting crystals with characteristic lengths <50 μm. Preliminary evidence of polymorph detection was also presented with recommendations for improvements in the technique.

We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting ... more We present a high-resolution miniature, light-weight fluorescence microscope with electrowetting lens and onboard CMOS for high resolution volumetric imaging and structured illumination for rejection of out-of-focus and scattered light. The miniature microscope (SIMscope3D) delivers structured light using a coherent fiber bundle to obtain optical sectioning with an axial resolution of 18 μm. Volumetric imaging of eGFP labeled cells in fixed mouse brain tissue at depths up to 220 μm is demonstrated. The functionality of SIMscope3D to provide background free 3D imaging is shown by recording time series of microglia dynamics in awake mice at depths up to 120 μm in the brain.

Optics Express, 2020

An optical switch based on an electrowetting prism coupled to a multimode fiber has demonstrated ... more An optical switch based on an electrowetting prism coupled to a multimode fiber has demonstrated a large extinction ratio with speeds up to 300 Hz. Electrowetting prisms provide a transmissive, low power, and compact alternative to conventional free-space optical switches, with no moving parts. The electrowetting prism performs beam steering of ±3° with an extinction ratio of 47 dB between the ON and OFF states and has been experimentally demonstrated at scanning frequencies of 100–300 Hz. The optical design is modeled in Zemax to account for secondary rays created at each surface interface (without scattering). Simulations predict 50 dB of extinction, in good agreement with experiment.

Scientific reports, Jan 25, 2018

We present a miniature head mounted two-photon fiber-coupled microscope (2P-FCM) for neuronal ima... more We present a miniature head mounted two-photon fiber-coupled microscope (2P-FCM) for neuronal imaging with active axial focusing enabled using a miniature electrowetting lens. We show three-dimensional two-photon imaging of neuronal structure and record neuronal activity from GCaMP6s fluorescence from multiple focal planes in a freely-moving mouse. Two-color simultaneous imaging of GFP and tdTomato fluorescence is also demonstrated. Additionally, dynamic control of the axial scanning of the electrowetting lens allows tilting of the focal plane enabling neurons in multiple depths to be imaged in a single plane. Two-photon imaging allows increased penetration depth in tissue yielding a working distance of 450 μm with an additional 180 μm of active axial focusing. The objective NA is 0.45 with a lateral resolution of 1.8 μm, an axial resolution of 10 μm, and a field-of-view of 240 μm diameter. The 2P-FCM has a weight of only ~2.5 g and is capable of repeatable and stable head-attachmen...

Biomedical optics express, 2017

Laser scanners are an integral part of high resolution biomedical imaging systems such as confoca... more Laser scanners are an integral part of high resolution biomedical imaging systems such as confocal or 2-photon excitation (2PE) microscopes. In this work, we demonstrate the utility of electrowetting on dielectric (EWOD) prisms as a lateral laser-scanning element integrated in a conventional 2PE microscope. To the best of our knowledge, this is the first such demonstration for EWOD prisms. EWOD devices provide a transmissive, low power consuming, and compact alternative to conventional adaptive optics, and hence this technology has tremendous potential. We demonstrate 2PE microscope imaging of cultured mouse hippocampal neurons with a FOV of 130 × 130 μm using EWOD prism scanning. In addition, we show simulations of the optical system with the EWOD prism, to evaluate the effect of propagating a Gaussian beam through the EWOD prism on the imaging quality. Based on the simulation results a beam size of 0.91 mm full width half max was chosen to conduct the imaging experiments, resultin...

Conference on Lasers and Electro-Optics, 2016

We demonstrate a large extinction ratio optical shutter using total internal reflection with an e... more We demonstrate a large extinction ratio optical shutter using total internal reflection with an electrowetting device. An on-off ratio of greater than 60 dB was measured. The device shows promise for chip-scale atomic-clocks and gyroscopes.

2015 Transducers - 2015 18th International Conference on Solid-State Sensors, Actuators and Microsystems (TRANSDUCERS), 2015

This paper presents the first reported specific heat capacity measurements of ultra-thin atomic l... more This paper presents the first reported specific heat capacity measurements of ultra-thin atomic layer deposited W/Al2O3 thin films. The thermal time constants of suspended ALD nanobridges were measured and a new model was derived to fit the data and extract the specific heat capacity. The accuracy of the new model was compared against a traditional model using finite element and analytical modeling. Application of these ultra-thin materials for microbolometer performance enhancement is discussed.

2002 IEEE International Conference on Industrial Technology, 2002. IEEE ICIT '02.

Micromachined thermal multimorph actuators for out-of-plane displacements have been designed and ... more Micromachined thermal multimorph actuators for out-of-plane displacements have been designed and fabricated by Multi-Users MEMS Process (MUMPs) with a post-processing bulk etching step. Micromachined actuators have potential applications in micromanipulation and nanoposition such as manipulation of scanning tunneling microscope (STM) tips, nanopositioner for nano-assembly, micro/nanorobots and cantilever-based nanosensors. The actuator consists of a multilayer micromachined beam constructed of various combinations of polysilicon, oxide and metal layers. The multimorph is heat by applying current to an embedded polysilicon wire to achieve beam bending The maximum tip deflection of 2.5 m with an input power of 40 mW is achieved. The maximum operating frequency of 2.7 kHz is measured by focus laser reflecting method. A design methodology, device fabrication, and device characterization are presented.

We present theoretical and experimental progress towards an atom transistor using ultra-cold Rb87... more We present theoretical and experimental progress towards an atom transistor using ultra-cold Rb87 atoms. Our transistor system will use a three well potential where tunneling between the two outside wells is controlled by the number of atoms in central well. In order to achieve realistic tunneling rates in the device, we create the potentials less than 1 micrometer away from an atom chip patterned with sub-micron wires. This scheme presents a host of technical challenges, including fabrication of chip features with adequate resolution and managing surface effects due to the proximity of the chip and the atoms. Noise limits of the system are discussed for both field fluctuations and atom number noise.

CLEO: 2015, 2015

We demonstrate an electrowetting-based variable prism with dual prism-lens operation. A prism ape... more We demonstrate an electrowetting-based variable prism with dual prism-lens operation. A prism apex angle change of 19° at 35 V and curvature change to infinite focal length at 18.9 V are demonstrated.

Ceramics are used in emerging MEMS technologies because of their diverse structural, chemical and... more Ceramics are used in emerging MEMS technologies because of their diverse structural, chemical and functional properties and because innovative precursor-based processing is leading to low-cost and flexible approaches to manufacturing.

Conference on Microtechnologies in Medicine and Biology, International, 2000

Presents a highly cost-effective sensor for intermittent measurement of average intracranial pres... more Presents a highly cost-effective sensor for intermittent measurement of average intracranial pressure. The key to the sensor's cost-effectiveness is its design for commercial-foundry fabrication and simple packaging approach. Unlike most conventional pressure sensors that require custom fabrication, the transducer chip in this work was fabricated entirely through a commercial CMOS process. The number of process steps required to fabricate an

Sensors and Actuators A: Physical, 2003

This work describes the design, fabrication, modeling, characterization and testing of a new clas... more This work describes the design, fabrication, modeling, characterization and testing of a new class of MEMS: micro igniters for ultrahightemperature (exceeding 1000 8C) ignition applications. Micro glow plugs (MGPs) were fabricated from polymer-derived silicon carbonnitride (Si-C-N), which is a recently-developed and highly refractory ceramic derived from a liquid polymer precursor. SiCN has been shown to possess outstanding mechanical robustness, corrosion resistance, and thermal shock resistance at ultrahigh-temperatures, making it an ideal material for harsh environment applications. The micro glow plug achieved temperatures of up to 1450 8C, with a response time of <1 s and power consumption of 3 W. Application as an ultrahigh-temperature igniter in both chip-scale and macro-scale reactions were demonstrated. Furthermore, polymer-derived ceramics (PDCs) being a relatively new class of materials, this work is the first to demonstrate the use of MEMS to obtain high-temperature properties of these new materials in situ. The device was used to obtain the Mott variable range hopping (VRH) parameters for temperature-dependence of resistivity in SiCN, as well as the range for the oxidation activation energy. The micro glow plug thus demonstrates both a new class of harsh-environment MEMS as well as a tool for in situ measurement of high-temperature properties in PDCs.

Sensors and Actuators A: Physical, 2007

Atomic layer deposition (ALD) was used to deposit an alternative dielectric barrier layer for use... more Atomic layer deposition (ALD) was used to deposit an alternative dielectric barrier layer for use in radio frequency microelectromechanical systems (rf MEMS). The layer is an alloy mixture of Al 2 O 3 and ZnO and is proposed for use as charge dissipative layers in which the dielectric constant is significant enough to provide a large down-state capacitance while the resistivity is sufficiently low to promote the dissipation of trapped charges. This paper investigates Al 2 O 3 /ZnO ALD alloys deposited at 100 and 177 • C and compares their material properties. Auger electron spectroscopy was used to determine the Zn concentrations in the alloy films, which was lower than expected. Atomic force microscopy images revealed an average surface roughness of 0.27 nm that was independent of deposition temperature and film composition. The dielectric constants of the Al 2 O 3 /ZnO ALD alloys films were calculated to be similar to pure Al 2 O 3 ALD, being ∼7. Indentation was used to ascertain the modulus and hardness of the ALD films. Both the modulus and hardness were found to increase for the greater deposition temperature. ALD-coated rf MEMS switches showed a low insertion loss, ∼0.35 dB, and a high isolation, 55 dB at 14 GHz. Mechanical actuation of the ALD-coated devices showed lifetimes of over 1 billion cycles.

IEEE Transactions on Advanced Packaging, 2003

We have developed an in-guide atom beamsplitter and demonstrated the coherent nature of the proce... more We have developed an in-guide atom beamsplitter and demonstrated the coherent nature of the process by observing interference between the split wavepackets. Pre-cooled atoms are captured by the on-chip waveguide and trapped by confining fields in a ``microtrap'' region of the guide. Atoms are then evaporatively cooled to form a Bose-Einstein condensate. Finally, we are able to split the condensate, propagate two wavepackets in opposite directions along the waveguide and read their relative phase by exposing the trapped BEC to a sequence of standing light pulses. We carefully aligned the standing light field with the waveguide by directly mounting mirrors on the chip substrate. Pre-cooled atoms reach the trapping region by following the guide through a 180-um-height tunnel under one of the mirrors. We control the phase shift between the two wavepackets by applying an external magnetic gradient parallel to the guide. After recombining the clouds, we observed coherence signal...

Physical Review A, 2004

A 87 Rb Bose-Einstein condensate (BEC) is produced in a portable atom-chip system less than 30ϫ 3... more A 87 Rb Bose-Einstein condensate (BEC) is produced in a portable atom-chip system less than 30ϫ 30 ϫ 15 cm, where the ultrahigh vacuum is maintained by a small, 8 L / s, ion pump and nonevaporable getter. An aluminum nitride chip with lithographically patterned copper is used to seal the vacuum system, provide the electrical feedthroughs, and create the magnetic trap potentials. All cooling and trapping processes occur 0.6-2.5 mm from ambient laboratory air. A condensate of about 2000 87 Rb atoms in F =2,m F = 2 is achieved after 4.21 s of rf forced evaporation. A magneto-optical trap lifetime of 30 s indicates the vacuum near the chip surface is about 10 −10 torr. This work suggests that a chip-based BEC-compatible vacuum system can occupy a volume of less than 0.5 L.