Abstract: A simultaneously super pulsed Q-switched CO2 laser system for material processing is disclosed. The system comprises sealed-off folded waveguides with folded mirrors that are thin film coated to select the output wavelength of the laser. The system also comprises a plurality of reflective devices defining a cavity; a gain medium positioned within the cavity for generating a laser beam; a cavity loss modulator for modulating the laser beam, generating thereby one or more laser pulses; a pulsed signal generation system connected to the cavity loss modulator for delivering pulsed signals to the cavity loss modulator thereby controlling the state of optical loss within the cavity; a control unit connected to the pulsed signal generation system for controlling the pulsed signal generation system; and a pulse clipping circuit receptive of a portion of the laser beam and connected to the pulsed signal generation system for truncating a part of the laser pulses.

Abstract: This disclosure discusses techniques for obtaining wavelength selected simultaneously super pulsed Q-switched and cavity dumped laser pulses utilizing high optical damage threshold electro-optic modulators, maintaining a zero DC voltage bias on the CdTe electro-optic modulator (EOM) so as to minimize polarization variations depending on the location of the laser beam propagating through the CdSe EOM crystal, as well as the addition of one or more laser amplifiers in a compact package and the use of simultaneous gain switched, Q-switched and cavity dumped operation of CO2 lasers for generating shorter pulses and higher peak power for the hole drilling, engraving and perforation applications.

Abstract: A clamping device for an RF excited laser is provided which reduces stress on ceramic components and also is less expensive than existing clamping devices. The RF excited laser lacking an electrode over the waveguide channel intersection regions. Ceramic covers are provided over a portion of these channel intersection regions to reduce plasma build up. Increased power is achieved by adding a fourth channel to a conventional waveguide to form a ring resonator. The optical component mount uses radial compressive forces to hold the optical component to a post, thereby preventing the face of the optical component from being distorted. Mirror mounts are also configured to allow more mirrors to be mounted at each end of the laser. The waveguide channel of the RF excited laser having a U-shaped cross section and an aspect ratio grater than one-to-one, which improves laser performance. A beam redirection device allows the laser head to serve as a mounting surface for other optical components.

Abstract: A photo-acoustic leak detection system for detecting a gas leaking from a component 30, includes at least two laser beams 24,26, incident on the component 30 and disposed so as to completely illuminate an inspection region 159 around at least a portion 28 of the component 30, each beam having a corresponding wavelength .lambda..sub.1 which is absorbed by the gas, the gas emitting an acoustic signal 36 when the gas absorbs light from at least one of the beams, an acoustic sensor 40, which receives the acoustic signals 36 and provides a sensor signal indicative thereof on a line 42 to a bandpass filter 44 and a synchronous detector 18 which provide a filtered signal indicative of the acoustic signal 36 on a line 50 to a signal processor 52. The processor 52 provides an output signal indicative of the leak in the component 30.

Abstract: A photo-acoustic leak detection system for detecting a gas leaking from a component includes a beam, having a wavelength, incident on the component and producing an acoustic signal. A second acoustic signal is also produced when an air source dilutes the gas leaking from the component. A signal processor receives sensor signals indicative of both acoustic signals and uses the second sensor signal as a non-leak baseline measurement and provides an output signal indicative of whether a leak exists.

Abstract: A photo-acoustic leak detection system for detecting a gas leaking from a component (30), includes at least one laser beam (20), incident on the component (30) and having a wavelength which is absorbed by the gas, the gas emitting a photo-acoustic signal (36) when the gas absorbs light from the beam (20), the beam (20) being pulsed at a pulse frequency, the pulse frequency being related to a detection frequency of the photo-acoustic signal and being a frequency at which the magnitude of background acoustic noise at the detection frequency is at a predetermined low level, at least one acoustic sensor (40), which receives the photo-acoustic signal (36) and provides a sensor signal on the line (42) indicative thereof to a filter (44) and a synchronous detector (18), which provide a filtered signal on a line (50) to a signal processor (52). The processor (52) provides an output signal on a line (54) indicative of the leak in the component.

Abstract: An amplitude modulated continuous wave (AMCW) laser radar (ladar) system is provided with a dual-wavelength source 10 which provides a dual wavelength signal 12 (one fixed and one chirped) which is launched down a fiber 28 to a target 38 and reflected back along the fiber 28 and the return detected by a detector 52. The transmitted signal is detected by a detector 56. The detectors 52, 56 provide an electrical return beat signal and reference beat signal, respectively, indicative of the difference between the wavelengths incident thereon. The signals are fed to a frequency mixer 60 which subtracts the two beat frequencies and signal processing logic 64 computes the distance to the target 38. Using dual wavelengths and beat frequencies provides a much broader chirp bandwidth than conventional ladar techniques, and allows for higher power sources, thereby reducing range error.

Abstract: A remote active multipoint fiber laser sensor includes a plurality of fiber lasers 12,14,16, each having a pair of Bragg gratings 18,20, embedded in a fiber 10 and excited by a common pump light 30. The lasers 12,14,16 lase at different longitudinal modes (lasing wavelengths) and emit light 32,34,36, at their respective wavelengths .lambda.1,.lambda.2,.lambda.n. The lasing wavelength of each laser shifts due to perturbations, such as strain or temperature, applied thereto. The output light 32,34,36 is fed to a spectrum analyzer 50 where the wavelength shift is analyzed. A signal processor 54 reads the wavelength shift and provides a signal on lines 56 indicative of the perturbation at each of the lasers/sensors 12-16. Alternatively, a single laser may be used as a single sensor. Alternatively, birefringent fiber may be used as the fiber cavities 21 and the two polarizations are beat together to form a lower difference or "beat" frequency, thereby allowing lower frequency detection devices to be used.

Abstract: A phase-locked ridge waveguide gas laser includes a body that circumferentially bounds an elongated internal space extending along a longitudinal main plane and bisected by a longitudinal central plane. The internal space contains a gaseous lasing medium that is excited at radio frequency with attendant light emission from the gaseous medium. Mirrors are so positioned relative to the body as to provide lasing of the light emission. Respective ridges partition the internal space into a plurality of laser resonator cavities each sustaining a guided mode of the lasing light emission. Each of the cavities extends longitudinally of the body and is spaced from an adjacent cavity by a predetermined distance in a width direction of the internal space.

Abstract: A phase-locked ridge waveguide gas laser includes a body that circumferentially bounds an internal space extending along a central plane and containing a gaseous lasing medium. The gaseous medium is excited at radio frequency with attendant light emission from the gaseous medium. Mirrors are so positioned relative to the body as to provide lasing of the light emission. Respective ridges partition the internal space into a plurality of cylindrical laser resonator cavities each sustaining a guided mode of the lasing light emission. Each of the cavities extends longitudinally of the body and is spaced from an adjacent cavity by a predetermined distance in a width direction of the internal space. The ridges are substantially cusp-shaped and extend into the internal space along a height dimension in respective aligned pairs.

Abstract: A phase-locked ridge waveguide gas laser includes a body having two major and two minor limiting surfaces together circumferentially bounding an internal space within the body, which contains a gaseous lasing medium. The gaseous medium is excited at radio frequency with attendant light emission from the gaseous medium. Mirrors are so positioned relative to the body as to provide lasing of the light emission. Respective ridges partition the internal space into at least three laser resonator cavities each sustaining a guided mode of the lasing light emission. The ridges extend in an alternative fashion from one and the other of the major surfaces of the body into the internal space and terminate short of the respectively other of the major surfaces to provide respective gaps. Each of these gaps connects two adjacent ones of the laser resonator cavities for phase-locking the guided modes in such cavities.

Abstract: A phase-locked staggered ridge array waveguide gas laser includes a body that circumferentially bounds an internal space extending along a central plane and containing a gaseous lasing medium. The gaseous medium is excited at radio frequency with attendant light emission from the gaseous medium. Mirrors are so positioned relative to the body as to provide lasing of the light emission. Two arrays of ridges extending into the internal space along a height dimension partition the internal space into two pluralities of laser resonator cavities each sustaining a guided mode of the lasing light emission. Each of the cavities extends longitudinally of the body and is spaced from an adjacent cavity in a width direction of the internal space.

Abstract: A compact distributed inductance RF-excited waveguide gas laser arrangement includes a housing which bounds an internal space, and a waveguide laser stack located in the internal space. The stack includes, in succession, a first electrode which may be constituted by a portion of the housing, a waveguide body bounding at least one laser cavity, a second electrode, a spacer body, and a plurality of flat inductor coils that extend along a major surface of the spacer body that faces away from the second electrode and are distributed along the length of the laser cavity. Each of the inductor coils has a first end electrically connected with the first electrode and a second end electrically connected with the second electrode so that, when alternating electric current at radio frequency is applied to one of the electrodes, the inductance of each of the inductor coils is arranged electrically in parallel with the capacitance formed between the first and second electrodes and transversely of the laser cavity.

Abstract: A phase locked ridge waveguide gas laser comprises a plurality of resonators formed in a ceramic body. The resonators are delineated by ridges which provide less than total separation therebetween and allow optical coupling between guided mode optical signals propagating therein.

Abstract: An improved RF-waveguide laser has a waveguide with an asymmetric cross section that provides improved suppression of high order modes and increased efficiency.

Abstract: A sensor employs a laser to obtain a collimated light beam for transmission across the gas effluent of a catalytic cracking process. Particulate matter entrained in the gas flow forward scatters light energy to a collecting aperture which, in turn focuses the scattered light on a first photodetector. A second photodetector receives directly transmitted light energy. A ratio between the output signals of the two photodetectors is derived and presented to a threshold level detector. If the magnitude of the scatter exceeds a predetermined level it is concluded that a catalyst load dump has occurred. The optical system is carefully selected to ensure that only light energy scattered from a sample volume within the entrained gas flow reaches the first photodetector. This is important because it prevents particulate matter on the surfaces of the transparent windows from affecting the operating of the sensor.

Abstract: An RF excited gas laser having an optical cavity that is also a resonant cavity in the RF region is improved by the spacing of discrete inductors at fixed points along the cavity so that the problem present in the prior art of nonuniform excitation of the discharge along the cavity is eliminated and the discharge is essentially uniform throughout the cavity volume.

Abstract: An RF-discharge waveguide laser having two parallel waveguides is improved by the addition of coupling channels which permit the plasma in said waveguides to communicate.

Abstract: A long rare-gas halide excimer light source excited by a capacitively coupled discharge pumps a dye laser with high efficiency in a configuration matched to the length of the discharge.

Abstract: A waveguide laser having a gain medium excited by a capacitively coupled self-sustained discharge is disclosed. The gain medium is disposed within a dielectric waveguide having a capillary bore centrally located therein. A gain medium such as a rare gas halide mixture is excited by a capacitively coupled discharge between a power electrode circumferentially and axially enveloping a central portion of the waveguide and ground electrodes disposed proximate the ends of the waveguide between the mirrors defining the optical cavity of the laser. A preferred embodiment of the laser further includes means for circulating the gain medium through the waveguide. The present invention is adapted for providing pulses of radiation having a wavelength in the ultraviolet and visible spectrum and pulse widths typically less than 30 nanoseconds with peak powers in excess of one kilowatt.