Disposal of residual radiation from a frequency-conversion process
Granted: June 10, 2008
Patent Number:
7385752
A frequency-conversion arrangement including one or more optically nonlinear crystals is located in an enclosure. Radiation residual from the frequency conversion is directed into an optical fiber having one end in the enclosure for receiving the residual radiation and an opposite end outside of the enclosure for disposing of the residual radiation outside of the enclosure.
Device for spectroscopy using charged analytes
Granted: June 10, 2008
Patent Number:
7385210
A device for spectroscopy using charged analytes has an electron generator, which sends electrons through membrane into a charging chamber. The thermal strain of the membrane may be lowered significantly if a material is selected for the membrane which contains at least one component from the group of oxides, nitrides, and carbides with at least one of the elements B, Al, C, Si, and Ti or polysilicon.
Security portal with THz trans-receiver
Granted: May 27, 2008
Patent Number:
7378658
A portal for security screening of transport passengers includes a THz trans-receiver. In one example of the portal, the trans-receiver includes a small-spot, reflective scanning arrangement including a single detector in a heterodyne receiver configuration. In another example, the trans-receiver includes a large-beam reflective scanning arrangement with the trans-receiver in a synthetic aperture radar (SAR) configuration.
Laser illuminated projection displays
Granted: April 8, 2008
Patent Number:
7355657
A projection video display includes a light source including an OPS-laser delivering laser radiation in multiple transverse modes (a multiple-transverse-mode OPS-laser). The display includes a spatial light modulator for spatially modulating the radiation from the multiple-transverse-mode OPS-laser in accordance with a portion of an image to be displayed. Projection optics project the spatially modulated light on a screen on which the image is to be displayed. In one example the…
Apparatus for projecting a line of light from a diode-laser array
Granted: April 8, 2008
Patent Number:
7355800
A line-of-light projecting module is illuminated by a diode-laser bar and includes light-pipe for homogenizing light from the diode-laser bar in the slow-axis. A shaping optics assembly directs the light emitted by the diode-laser bar into the entrance end of the light-pipe as a diverging beam in the slow-axis and as a collimated beam in the fast-axis. The light propagates through the light-pipe unguided in the fast axis. The light is guided by the light-pipe in the slow-axis, and…
Identification of hidden objects by terahertz heterodyne laser imaging
Granted: March 18, 2008
Patent Number:
7345279
A method for inspecting a package to identify an object concealed in the package includes passing two beams of THz-radiation through the package. The frequency of THz radiation in one beam is different from that in the other, and the beams are at an angle to each other. Each of the transmitted beams is used to form an image of the package and the object. The absorption coefficient of the object is determined from the two images. The material of the object is determined from the…
Frequency domain equalization of communication signals
Granted: March 18, 2008
Patent Number:
7346013
A system and method for estimating a channel spectrum. The method includes: (a) receiving an input signal from a channel, where the input signal includes one or more major echoes and zero or more minor echoes introduced by the channel; (b) identifying the one or more major echoes present in the input signal; (c) identifying the minor echoes from a filtered autocorrelation function of the input signal in response to a determination that there is only one major echo; (d) identifying the…
Wavelength normalized depolarization ratio lidar
Granted: March 4, 2008
Patent Number:
7339670
A remote sensing optical system and method is disclosed that permits detection and discrimination of aerosols. The system outputs a plurality of wavelengths and is equipped with a polarization sensitive receiver capable of measuring the scattered energy in two orthogonal polarization states. By normalizing the depolarization to the total energy received and calculating the ratio of normalized depolarization at different wavelengths it is possible to use this ratio to discriminate…
Apparatus for combining beams from repetitively pulsed lasers along a common path
Granted: February 26, 2008
Patent Number:
7336691
Two pulse sequences are delivered by two lasers. A rotating segmented mirror having one or more reflective areas and one or more transmissive areas is rotated synchronously with the delivery of the pulse sequences to transmit pulses from one sequence, and to reflect pulses from the other sequence at intervals.
Apparatus for projecting a reduced image of a photomask using a schwarzschild objective
Granted: February 19, 2008
Patent Number:
7331676
An optical system for projecting an image of a photomask on a substrate, using a Schwarzschild objective includes an excimer laser, beam shaping optics for shaping a laser beam from the laser and a beam-dividing prism. The beam-dividing prism has a dividing-face including four facets inclined at an angle to each other. The four facets divide the shaped beam into four beam-portions propagating at an angle to the system axis. The beam-portions overlap at the photomask and mutually diverge…
Apparatus and method for stabilizing lasers using dual etalons
Granted: February 5, 2008
Patent Number:
7327471
Method and apparatus are disclosed that enable lasers to be stabilized in frequency to a high precision while simultaneously enabling rapid re-acquisition of stabilization control loops in the event of frequency locking loss. The principle of operation is to incorporate two etalons, one having a high finesse for frequency high stability, and one having a low finesse for wide error signal locking range, and electronics that pass control between two control systems in such a manner that…
Injection locking Q-switched and Q-switched cavity dumped COlasers for extreme UV generation
Granted: February 5, 2008
Patent Number:
7327769
A CO2 laser reference oscillator (RO) can provide injection seeding to a Q-switched (QS) or Q-switched cavity dumped (QSCD) CO2 laser, where the output frequency of the RO laser is locked to the peak of the laser line by the use of appropriate electronics to dither one of the resonator mirrors of the reference oscillator. This injected radiation seeds the radiation building up within the Q-switched laser cavity, such that the oscillating frequency favors the wavelength of the injected…
Attenuator for high-power unpolarized laser beams
Granted: February 5, 2008
Patent Number:
7327518
A method for attenuating an unpolarized laser beam includes separating the laser beam into two plane-polarized beams. The plane-polarized beams are polarization rotated. Each of the polarization-rotated beams is separated into two plane-polarized portions. One of the portions of one polarization-rotated beam is combined with one of the portions of the other polarization-rotated beam to provide an attenuated output-beam.
Variable pulse repetition frequency passively Q-switched laser
Granted: January 15, 2008
Patent Number:
7319708
A passive Q-switch element is disclosed that permits operating a laser with a variable pulse repetition frequency (PRF). The Q-switch comprises two wedges of material, one made from saturable absorber material, the other from transparent material, with the two wedges mounted together to form a constant optical thickness block. By translating the block transversely to a laser beam the amount of saturable absorber material seen by the laser beam is altered and as a result the PRF of the…
Laser beam transformation and combination using tapered waveguides
Granted: December 25, 2007
Patent Number:
7313299
A system for transmitting the spatial profile of laser beams with particular applicability to coherently combine laser beams into one beam. The system includes a tapered waveguide with an inlet and outlet at ends of two waveguide elements each having a reflective surface facing into the waveguide. The reflective surfaces are non-parallel such that the inlet height is different than the outlet height, e.g., inlet height greater than outlet height. The system includes a beam input assembly…
Optically pumped edge-emitting semiconductor laser
Granted: November 27, 2007
Patent Number:
7300809
A multilayer semiconductor laser includes a substrate on which is formed a semiconductor multilayer heterostructure divided into a plurality of electrically pumped regions and an elongated optically pumped region. The electrically pumped regions generate and deliver optical pump radiation laterally into the elongated optically pumped region. Output radiation is generated and delivered by the optically pumped region.
Double-pass fiber amplifier
Granted: October 30, 2007
Patent Number:
7289263
Several examples of double-pass fiber amplifiers including a polarization maintaining (PM) gain-fiber are disclosed. In each example, input and twice-amplified output are separated by an all-fiber, polarization-maintaining polarization splitter combiner. The examples include double-pass fiber amplifiers not including any bulk components and double pass fiber amplifiers including a bulk component or a Faraday rotating mirror located in a position in the amplifier wherein the component is…
Optical fiber coupling arrangement
Granted: October 23, 2007
Patent Number:
7286283
Apparatus for optically pumping a clad amplifier fiber includes one or more transmission fibers arranged and configured to insert pump-light from a pump light source such as a diode-laser into the cladding of the amplifier fiber. The pump light propagates through the cladding and a portion of the pump light is absorbed in the doped core of the amplifier fiber. At least one of the transmission fibers is arranged to receive an unabsorbed portion of the propagated pump light from the…
Electro-optical modulator module for COlaser Q-switching, mode-locking, and cavity dumping
Granted: October 9, 2007
Patent Number:
7280569
Various electro-optical modulator module designs are presented, which can provide for uniform, symmetric, and efficient heat removal for mode-locking, Q-switching, and/or cavity dumping operations. Heat can be uniformly extracted from an EO crystal without imposing undue stress, thereby preventing birefringence and laser beam degradation. A liquid-cooling approach can be used for high-duty operations, such as mode-locking operations. Efficient heat removal can prevent thermal run-away…
Method for manufacturing a multimode fiber pump power combiner
Granted: September 25, 2007
Patent Number:
7272956
A multimode to low-mode optical fiber is constructed by forming a plurality of multimode optical fibers into a fiber bundle. The bundle is then selectively heated and drawn to form a bi-tapered fiber bundle having a central straight portion in which the multimode fibers are fused into a single length of fiber. During the drawing step, measures are taken to provide an aperture extending through the bi-tapered bundle, including the single straight portion of the bundle. An optical fiber…
