High-contrast wide-field evanescent wave illuminated subdiffraction imaging

2017 ◽  
Vol 42 (21) ◽  
pp. 4569 ◽  
Author(s):  
Chenlei Pang ◽  
Xiaowei Liu ◽  
Minghua Zhuge ◽  
Xu Liu ◽  
Michael Geoffrey Somekh ◽  
...  
Keyword(s):  
Evanescent Wave ◽  
Wide Field ◽  
High Contrast

scholarly journals MEMS Deformable Mirrors for Space-Based High-Contrast Imaging

Micromachines ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 366 ◽  
Author(s):  
Rachel E. Morgan ◽  
Ewan S. Douglas ◽  
Gregory W. Allan ◽  
Paul Bierden ◽  
Supriya Chakrabarti ◽  
...  
Keyword(s):  
High Altitude ◽  
Space Environment ◽  
Optical Systems ◽  
Sounding Rocket ◽  
Deformable Mirrors ◽  
Wide Field ◽  
High Contrast ◽  
Contrast Imaging ◽  
Wavefront Control ◽  
High Contrast Imaging

Micro-Electro-Mechanical Systems (MEMS) Deformable Mirrors (DMs) enable precise wavefront control for optical systems. This technology can be used to meet the extreme wavefront control requirements for high contrast imaging of exoplanets with coronagraph instruments. MEMS DM technology is being demonstrated and developed in preparation for future exoplanet high contrast imaging space telescopes, including the Wide Field Infrared Survey Telescope (WFIRST) mission which supported the development of a 2040 actuator MEMS DM. In this paper, we discuss ground testing results and several projects which demonstrate the operation of MEMS DMs in the space environment. The missions include the Planet Imaging Concept Testbed Using a Recoverable Experiment (PICTURE) sounding rocket (launched 2011), the Planet Imaging Coronagraphic Technology Using a Reconfigurable Experimental Base (PICTURE-B) sounding rocket (launched 2015), the Planetary Imaging Concept Testbed Using a Recoverable Experiment - Coronagraph (PICTURE-C) high altitude balloon (expected launch 2019), the High Contrast Imaging Balloon System (HiCIBaS) high altitude balloon (launched 2018), and the Deformable Mirror Demonstration Mission (DeMi) CubeSat mission (expected launch late 2019). We summarize results from the previously flown missions and objectives for the missions that are next on the pad. PICTURE had technical difficulties with the sounding rocket telemetry system. PICTURE-B demonstrated functionality at >100 km altitude after the payload experienced 12-g RMS (Vehicle Level 2) test and sounding rocket launch loads. The PICTURE-C balloon aims to demonstrate 10 - 7 contrast using a vector vortex coronagraph, image plane wavefront sensor, and a 952 actuator MEMS DM. The HiClBaS flight experienced a DM cabling issue, but the 37-segment hexagonal piston-tip-tilt DM is operational post-flight. The DeMi mission aims to demonstrate wavefront control to a precision of less than 100 nm RMS in space with a 140 actuator MEMS DM.

Pretectal Neurons Optimized for the Detection of Saccade-Like Movements of the Visual Image

2001 ◽  
Vol 85 (4) ◽  
pp. 1512-1521 ◽  
Author(s):  
N.S.C. Price ◽  
M. R. Ibbotson
Keyword(s):  
Spatial Frequency ◽  
Second Harmonic ◽  
Temporal Frequency ◽  
Receptive Fields ◽  
High Spatial Frequency ◽  
Sine Wave ◽  
Wide Field ◽  
Visual Response ◽  
High Contrast ◽  
Sine Wave Gratings

The visual response properties of nondirectional wide-field sensitive neurons in the wallaby pretectum are described. These neurons are called scintillation detectors (SD-neurons) because they respond vigorously to rapid, high contrast visual changes in any part of their receptive fields. SD-neurons are most densely located within a 1- to 2-mm radius from the nucleus of the optic tract, interspersed with direction-selective retinal slip cells. Receptive fields are monocular and cover large areas of the contralateral visual field (30–120°). Response sizes are equal for motion in all directions, and spontaneous activities are similar for all orientations of static sine-wave gratings. Response magnitude increases near linearly with increasing stimulus diameter and contrast. The mean response latency for wide-field, high-contrast motion stimulation was 43.4 ± 9.4 ms (mean ± SD, n = 28). The optimum visual stimuli for SD-neurons are wide-field, low spatial frequency (<0.2 cpd) scenes moving at high velocities (75–500°/s). These properties match the visual input during saccades, indicating optimal sensitivity to rapid eye movements. Cells respond to brightness increments and decrements, suggesting inputs from on and off channels. Stimulation with high-speed, low spatial frequency gratings produces oscillatory responses at the input temporal frequency. Conversely, high spatial frequency gratings give oscillations predominantly at the second harmonic of the temporal frequency. Contrast reversing sine-wave gratings elicit transient, phase-independent responses. These responses match the properties of Y retinal ganglion cells, suggesting that they provide inputs to SD-neurons. We discuss the possible role of SD-neurons in suppressing ocular following during saccades and in the blink or saccade-locked modulation of lateral geniculate nucleus activity to control retino-cortical information flow.

High-contrast epi-fluorescence wide-field imaging of biological cells using integrating-bucket method

2015 ◽  
Vol 355 ◽  
pp. 427-432 ◽  
Author(s):  
K.S. Park ◽  
W.J. Choi ◽  
J.B. Eom ◽  
K.S. Chang ◽  
B.H. Lee
Keyword(s):  
Wide Field ◽  
Biological Cells ◽  
High Contrast ◽  
Field Imaging ◽  
Wide Field Imaging

Development of a Computer-Controlled 120kV High-Performance Tem

1996 ◽  
Vol 54 ◽  
pp. 446-447
Author(s):  
H. Kobayashi ◽  
I. Nagaoki ◽  
E. Nakazawa ◽  
T. Kamino
Keyword(s):  
High Resolution ◽  
High Performance ◽  
Spherical Aberration ◽  
Focal Length ◽  
Chromatic Aberration ◽  
Objective Lens ◽  
Wide Field ◽  
High Contrast ◽  
Computer Controlled ◽  
The Magnetic Field

A new computer controlled 120kV high performance TEM has been developed(Fig. 1). The image formation system of the microscope enables us to observe high resolution, wide field,and high contrast without replacing the objective lens pole-piece. The objective lens is designed for high- contrast (HC) and high-resolution(HR) modes, and consists of a double gap and two coils. A schematic drawing of the objective lens and the strength of the magnetic field of the lens is described in Fig.2. When the objective lens is used in HC mode, upper and lower coils are operated at a lens current of same polarity to form the long focal length. The focal length(fo), spherical aberration coefficient(Cs) and chromatic aberration coefficient (Cc) in HC mode at 100kV are 6.5, 3.4 and 3.1mm, respectively. Magnification range at HC mode is × 700 to × 200,000. The viewing area with an objective aperture of a diameter of 10μm is 160mm in diameter. In HR mode, the polarity of lower coil current is reversed to form a shorter focal length for high resolution image observation. The fo, Cs and Cc of the objective lens in HR mode at lOOkV are 3.1, 2.8 and 2.3mm, respectively. The highest magnification in HR mode is × 600,000.

scholarly journals Fusion of Constitutive Membrane Traffic with the Cell Surface Observed by Evanescent Wave Microscopy

2000 ◽  
Vol 149 (1) ◽  
pp. 33-40 ◽  
Author(s):  
Derek Toomre ◽  
Jürgen A. Steyer ◽  
Patrick Keller ◽  
Wolfhard Almers ◽  
Kai Simons
Keyword(s):  
Cell Surface ◽  
Vesicular Stomatitis Virus ◽  
Evanescent Wave ◽  
Total Internal Reflection ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Wide Field ◽  
Protein Fusion ◽  
Vesicular Stomatitis Virus Glycoprotein ◽  
Vesicular Stomatitis

Monitoring the fusion of constitutive traffic with the plasma membrane has remained largely elusive. Ideally, fusion would be monitored with high spatial and temporal resolution. Recently, total internal reflection (TIR) microscopy was used to study regulated exocytosis of fluorescently labeled chromaffin granules. In this technique, only the bottom cellular surface is illuminated by an exponentially decaying evanescent wave of light. We have used a prism type TIR setup with a penetration depth of ∼50 nm to monitor constitutive fusion of vesicular stomatitis virus glycoprotein tagged with the yellow fluorescent protein. Fusion of single transport containers (TCs) was clearly observed and gave a distinct analytical signature. TCs approached the membrane, appeared to dock, and later rapidly fuse, releasing a bright fluorescent cloud into the membrane. Observation and analysis provided insight about their dynamics, kinetics, and position before and during fusion. Combining TIR and wide-field microscopy allowed us to follow constitutive cargo from the Golgi complex to the cell surface. Our observations include the following: (1) local restrained movement of TCs near the membrane before fusion; (2) apparent anchoring near the cell surface; (3) heterogeneously sized TCs fused either completely; or (4) occasionally larger tubular-vesicular TCs partially fused at their tips.

scholarly journals High-contrast, synchronous volumetric imaging with selective volume illumination microscopy

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Thai V. Truong ◽  
Daniel B. Holland ◽  
Sara Madaan ◽  
Andrey Andreev ◽  
Kevin Keomanee-Dizon ◽  
...  
Keyword(s):  
Light Field ◽  
Sample Volume ◽  
Wide Field ◽  
High Contrast ◽  
Background Signal ◽  
Low Contrast ◽  
Volumetric Imaging ◽  
Larval Zebrafish ◽  
Volume Of Interest ◽  
Symbiotic Partner

AbstractLight-field fluorescence microscopy uniquely provides fast, synchronous volumetric imaging by capturing an extended volume in one snapshot, but often suffers from low contrast due to the background signal generated by its wide-field illumination strategy. We implemented light-field-based selective volume illumination microscopy (SVIM), where illumination is confined to only the volume of interest, removing the background generated from the extraneous sample volume, and dramatically enhancing the image contrast. We demonstrate the capabilities of SVIM by capturing cellular-resolution 3D movies of flowing bacteria in seawater as they colonize their squid symbiotic partner, as well as of the beating heart and brain-wide neural activity in larval zebrafish. These applications demonstrate the breadth of imaging applications that we envision SVIM will enable, in capturing tissue-scale 3D dynamic biological systems at single-cell resolution, fast volumetric rates, and high contrast to reveal the underlying biology.

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