A5064704578- Advanced Optical Sensing Technologies
- Laser Design and Applications
- Solid State Laser Technologies
- Remote Sensing and LiDAR Applications
- Ocular and Laser Science Research
- Geophysics and Gravity Measurements
- Planetary Science and Exploration
- GNSS positioning and interference
- Astronomical Observations and Instrumentation
- Spectroscopy and Laser Applications
- Adaptive optics and wavefront sensing
- Inertial Sensor and Navigation
- Semiconductor Lasers and Optical Devices
- Photonic and Optical Devices
- Geophysics and Sensor Technology
- Optical Systems and Laser Technology
- Atmospheric aerosols and clouds
- Advanced Fiber Laser Technologies
- Advanced Frequency and Time Standards
- Space Satellite Systems and Control
- Satellite Image Processing and Photogrammetry
- 3D Surveying and Cultural Heritage
- Atmospheric and Environmental Gas Dynamics
- Astro and Planetary Science
- Optical Wireless Communication Technologies
Sigma Space (United States)
2008-2021
University of Michigan
2011
University of California, San Diego
2010
California Institute of Technology
2010
Goddard Space Flight Center
1994-2005
Brewster Place
2005
University of California, Los Angeles
2000
Institute for Law and Justice
2000
American Federation of Labor and Congress of Industrial Organizations
2000
Stanford Medicine
2000
In optimizing passively Q-switched lasers, there is a unique choice of output coupler and unsaturated absorber transmission which maximizes the laser energy efficiency for each three-way combination gain medium, pump intensity (i.e, inversion density). present paper, we generalize solve three coupled differential equations describe to obtain closed form solutions key parameters such as pulsewidth. We then apply Lagrange multiplier technique determine optimum mirror reflectivities...
The general equations describing Q-switched laser operation are transcendental in nature and require numerical solutions, which greatly complicates the optimization of real devices. Here, it is shown that, using mathematical technique Lagrange multipliers, one can derive simple analytic expressions for all key parameters optimally coupled laser, i.e. uses an optimum reflector to obtain maximum efficiency a given pump level. These be expressed as functions single dimensionless variable z,...
This paper is intended to be a nonmathematical tutorial on the subject of satellite laser ranging (SLR) with an emphasis characteristics and capabilities present future field-hardware operational methods. Following brief introduction basic concept SLR many science applications both lunar ranging, we discuss developmental history each major components which make up machine, i.e., transmitter, photomultiplier, discriminator, time interval unit. At same time, attempt identify sources range...
The gain of centrally obscured optical transmitting antennas is analyzed in detail. calculations, resulting near- and far-field antenna patterns, assume a circular illuminated by laser operating the TEM(00) mode. A simple polynomial equation derived for matching incident source distribution to general configuration maximum on-axis gain. An interpretation resultant curves allows number auxiliary design be drawn that display losses due pointing errors cone angle beam far field as function...
A general theory of finite-aperture waveguide-laser resonators is developed which represents the external reflectors by matrices couple linearly polarized waveguide modes having same azimuthal symmetry. The allows determination resonator efficiency, frequencies, and laser near- far-field patterns. Computations coupling loss for fundamental mode as a function mirror curvature, separation, aperture are in good agreement with recent infinite-aperture calculations limit large apertures indicate...
Several scanning, single photon sensitive, 3D imaging lidars are herein described that operate at aircraft above ground levels (AGLs) between 1 and 11 km, speeds in excess of 200 knots. With 100 beamlets laser fire rates up to 60 kHz, we, the Sigma Space Corporation (Lanham, MD, USA), have interrogated 6 million pixels per second, all which can record multiple returns from volumetric scatterers such as tree canopies. High range resolution has been achieved through use subnanosecond...
Expressions are derived for the gain of a centrally obscured, circular optical antenna when used as collecting and focusing optics in laser receiver which include losses due to (1) blockage incoming light by central obscuration, (2) spillover energy at detector, (3) effect local oscillator distribution case heterodyne or homodyne detection. Numerical results presented direct detection three types distributions (uniform, Gaussian, matched) The several graphs that allow rapid evaluation an...
The difference in notations used by researchers the dielectric waveguide field and those primarily interested lasers is discussed, equations for components of various modes large radius hollow waveguides are rederived terms more widely notation. Certain linear combinations these that give linearly polarized distributions then considered to be launched into free-space at a termination. resultant Fresnel Fraunhofer useful identifying oscillation choosing mirror apertures will restrict on...
Phobos Laser Ranging (PLR) is a concept for space mission designed to advance tests of relativistic gravity in the solar system. PLR's primary objective measure curvature around Sun, represented by Eddington parameter $\gamma$, with an accuracy two parts $10^7$, thereby improving today's best result orders magnitude. Other goals include measurements time-rate-of-change gravitational constant, $G$ and inverse square law at 1.5 AU distances--with up orders-of-magnitude improvement each. The...
A paraxial resonance equation is derived. This gives the mirror separation as a function of radii curvature mirrors and an integer N which number return transits necessary to form closed path rays. Differentiating formula for relative mode density separation. It shown that output power from laser incorporating solid inversely proportional density. In case hole coupling, follows same general profile but dips in occur at separations corresponding configurations modes characterized by low...
The conventional rate equations for a Q-switched laser are augmented to explicitly include the effects of time- and level-dependent pumping, thermalization among sublevels in upper lower multiplets, multiplet relaxation homogeneously broadened four-level medium. To make numerical computations more generally valid, we introduce number dimensionless variables. We show that initial set five coupled differential can be reduced simple two inversion density photon flux. Via modeling, have...
Projects of the growth earth-sensing systems for latter half 1980's show a data transmission requirement 300 Mbit/s and above. Mission constraints objectives lead to conclusion that most efficient technique return from sensing satellite ground station is through geosynchronous relay satellite. Of two links are involved (sensing ground), laser system attractive space-to-space link. A five-year program was conducted which has shown basic technical feasibility accomplishing this link with CO...
Get PDF Email Share with Facebook Tweet This Post on reddit LinkedIn Add to CiteULike Mendeley BibSonomy Citation Copy Text John J. Degnan and Bernard Klein, "Optical Antenna Gain. 2:Receiving Antennas. Errata," Appl. Opt. 13, 2762-2762 (1974) Export BibTex Endnote (RIS) HTML Plain alert Save article
The Geoscience Laser Altimetry/Ranging System (GLARS) is a planned highly precise laser distance-measuring system to be used for geoscience measurements requiring extremely accurate geodetic observations from space platform. combines the attributes of pointable ranging making retroreflectors placed on ground with those nadir-looking altimeter height ground, ice sheet, and oceanic surfaces. In mode, centimeter-level baseline station coordinate determinations will made grids consisting 100 200...
The small-signal gain and saturation intensity in a waveguide CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> laser are determined by means of least squares curve-fitting technique. method allows the simultaneous estimation two parameters from an arbitrary number data points relating power output to incidence angle internal coupling plate.
Sigma Space Corporation has recently developed a compact 3D imaging and polarimetric lidar suitable for use in small aircraft or mini-UAV. A frequency-doubled Nd:YAG microchip laser generates 6 microjoule, subnanosecond pulses at fire rates up to 22 kHz. Diffractive Optical Element (DOE) breaks the 532 nm beam into 10x10 array of Gaussian beamlets, each containing about 1 mW power (50 nJ @ 20 kHz). The reflected radiation beamlet is imaged by receive optics onto individual pixels high...