Abstract: An excimer or molecular fluorine laser includes a discharge chamber filled with a gas mixture, multiple electrodes within the discharge chamber connected to a power supply circuit for energizing the gas mixture, and a resonator including the discharge chamber and a pair of resonator reflectors for generating an output laser beam. One of the resonator reflectors is an output coupling interferometer including a pair of opposing reflecting surfaces tuned to produce a reflectivity maximum at a selected wavelength for narrowing a linewidth of the output laser beam. One of the pair of opposing reflecting surfaces is configured such that the opposing reflecting surfaces of the interferometer have a varying optical distance therebetween over an incident beam cross-section which serves to suppress outer portions of the reflectivity maximum to reduce spectral purity.

Abstract: A device for generating blue or green laser light by the use of a device comprising an infrared high power semiconductor laser or an infrared high power semiconductor laser bar or array, a diffractive optical device, and an optical device utilizing a non-linear crystal to generate the blue or green laser light. In one embodiment, the diffractive optical device comprises a volume holographic transmission grating and the optical device comprises a ring resonator. In another embodiment, the diffractive optical device comprises a reflective diffraction grating feedback mechanism and the optical device comprises a ring resonator. In another embodiment, the optical device comprises a parabolic or non-planar feedback mechanism and a ring resonator. In another embodiment, the diffractive optical feedback device, which can be in the form of digital/binary optics, is attached to the semiconductor laser source.

Abstract: The present invention advantageously enables single-mode lasing at higher pump power and further enables general reduction of the lasing radiation bandwidth. This is accomplished by producing an appropriate spatial gain distribution inside the laser medium. The present invention further enables advantageous selection of a particular photonic mode for lasing at that mode in a periodic laser by varying spatial gain distribution within the periodic laser medium. Photonic mode selection by varying gain distribution within the laser medium is accomplished in accordance with various embodiments of the present invention.

Abstract: A high-energy laser Faraday rotator is used in an optical system in which the Faraday rotator absorbs laser light energy of more than 20 mW. The Faraday rotator includes a bismuth-substituted rare-earth iron garnet single crystal film grown as a Faraday rotator by using a liquid phase epitaxial method, and non-magnetic substrate having a side surface on which the bismuth-substituted rare-earth iron garnet single crystal film is formed.

Abstract: A monolithically integrated light source and frequency discriminator has a section in which a single frequency optical signal is produced and a section in which the frequency is sensed. The output of the optical discriminator is connected to a controller for stabilizing the output frequency of the light source.

Abstract: A method and apparatus of selecting a predetermined number of pulses from a stream of laser pulses is described. The number of pulses is determined by the operator from the laser pulse repetition rate and the desired number of pulses. The invention comprises synchronizing the laser pulses with the start of the pulse selection, allowing the predetermined count of laser pulses to pass a blocking mechanism; and finally blocking the pulses after the pulses have passed.

Abstract: An excimer laser apparatus comprises a container sealing a laser gas including a halogen gas therein, a pair of discharge electrodes disposed in the container for inducing an electric discharge capable of oscillating a laser light, and a circulating fan with a shaft for producing a high-speed laser gas stream between a pair of the discharge electrodes. Both ends of the shaft are rotatably supported by rotor-stator mechanisms, or one end of the shaft is rotatably supported by a rotor-stator mechanism, and the other end of the shaft is supported by a magnetic bearing. The rotor-stator mechanism comprises a rotor attached to the shaft of the circulating fan, a stator provided at a position opposed to the rotor, an electric motor winding provided in the stator for applying torque to the rotor, and a position control winding provided in the stator for producing a magnetic force to levitate and support the rotor.

Abstract: Provided are complex optical material that trivalent ytterbium ion is codoped into single crystalline, poly crystalline or amorphous material containing tetravalent chromium ion or trivalent vanadium ion as an active medium, and a using method of the material. In application of the material to solid-state lasers, optical fiber amplifiers and the likes, when excitation occurs in the 980 nm wavelength band in which absorption strongly occurs at the ytterbium ion with avoiding the wavelength range of 600˜800 nm in which the excited-state absorption occurs at the chromium ion, the energy is transferred from the ytterbium ion to the chromium ion to emit fluorescence in the range of 1200˜1600 nm wavelength. Accordingly, the present invention is to solve the problem of the excitation efficiency decrease of the tetravalent chromium ion due to the excited-state absorption and to enhance the fluorescence emission intensity.

Abstract: A chiral laser apparatus comprises a layered structure configured to produce a photonic stop band, the layered structure including a upper chiral material layer, a middle excitable light-emitting layer, and a lower chiral material layer and an excitation source that, when applied to the layered structure, causes the middle light-emitting layer to emit electromagnetic radiation, such that polarized lasing at a lasing wavelength occurs in a direction perpendicular to the layered structure. The middle light-emitting layer may be configured to produce a defect such that lasing advantageously occurs at a wavelength corresponding to a localized photonic state within the photonic stop band. The excitation source may be an electrical power source connected to the layered structure via two or more electrodes. In another embodiment of the invention, the layered structure is replaced with a homogeneous chiral material doped with a light-emitting material.

Abstract: A laser radiating optical system is composed of a laser diode and two mutually independent shaping optical systems. The laser diode emits a laser beam that has a Gaussian intensity distribution and that diverges with a large divergence angle in a first direction and with a small divergence angle in a second direction perpendicular to the first direction. The first shaping optical system makes the intensity distribution even with respect to the first direction, and the second shaping optical system makes the intensity distribution even with respect to the second direction. The shaping optical systems are each composed of a collimator lens and a diffractive element for shaping, and the diffractive elements of the two shaping optical systems are given substantially equal numerical apertures.

Abstract: A fiber grating stabilized pump laser achieves power stability with a relatively low grating reflectivity of 1.0 to 2.3%. Substantial laser diode output facet reflectivity is provided, between 3.0 and 5.5%. When the optical fiber system provides for no polarization control between the grating and the diode laser, the power reflectivity of the grating, is preferably between 1.7 and 2.3%. The power reflectivity of the laser diode output facet is preferably between 3.4 and 4.9%. In contrast, when provisions are made for polarization control between the grating and laser diode, even lower grating reflectivities are possible, between 1.0 and 2.3%.

Abstract: A defect causing a localized state is induced in a chiral structure composed of multiple chiral elements by twisting one element of the chiral structure with respect to the other elements along a common longitudinal axis such that directors of the element molecular layers that are in contact with one another are disposed at a particular “twist” angle therebetween, the twist angle being greater than a shift angle between directors of consecutive layers. The chiral twist structure may be utilized in a variety of applications such as filters, lasers and detectors. The defect caused by the twist may be made tunable by providing a tuning device for ly rotating one or more of the chiral elements with respect to one another to vary the twist angle and thus vary the position of the induced defect within a photonic stop band. Tunable defects may be advantageously utilized to construct wavelength tunable chiral filters, detectors and lasers.

Abstract: A tunable laser has a fibre Bragg grating anchored at each to relatively movable fixtures and an actuator coupled to the fixtures for creating relative movement that longitudinally stretches or compresses the fibre Bragg grating. Measuring means are arranged to directly monitor a longitudinal separation between the fixtures and a microprocessor that is programmed to respond to signals from the measuring means controls the actuator to change the separation between the fixtures to tune the laser to a desired wavelength.

Abstract: A molecular fluorine (F2) laser is provided wherein the gas mixture includes molecular fluorine for generating an emission spectrum including two or three closely spaced lines around 157 nm. An optical method and means are provided for selecting an emission line from among the plurality of closely spaced emission lines of the molecular fluorine laser gas volume and broadening the spectrum of said selected emission line. This approach of broadening the spectrum reduces the coherence length of the output beam. As a result, speckle may be reduced or avoided in microlithography applications.

Abstract: A method and apparatus are provided for temporally stretching and smoothing of the pulses of an output beam of excimer and lithography lasers. The method and apparatus are based upon providing an optical delay line or circuit having a plurality of optical reflectors and a plurality of beam recombiners or splitters so arranged as to divide the pulse into numerous portions which vary in their travel time through the circuit. As a result, the energy of the incident pulse is greatly stretched and smoothed.

Abstract: A method and apparatus is provided for stabilizing output beam parameters of a gas discharge laser by maintaining a constituent gas of the laser gas mixture at a predetermined partial pressure using a gas supply unit and a processor. The constituent gas of the laser gas mixture is provided at an initial partial pressure and the constituent gas is subject to depletion within the laser discharge chamber. Injections of the constituent gas are performed each to increase the partial pressure by a selected amount in the discharge chamber preferably less than 0.2 mbar per injection. A number of successive injections is performed at selected intervals to maintain the constituent gas substantially at the initial partial pressure for maintaining stable output beam parameters. The amount per injection and/or the interval between injections may be varied based on the measured value of the driving voltage and/or a calculated amount of the constituent gas in the discharge chamber.

Abstract: An efficient frequency-converted solid state laser that outputs a single beam utilizing an angled reflector situated within the laser cavity. The laser comprises an optical cavity including a first reflector and a second reflector. A gain medium situated within the optical cavity is energized by a pump source to excite a laser emission at a fundamental wavelength. A nonlinear material is arranged within the optical cavity to convert the laser emission to a second wavelength. The angled reflector, which is reflective of the second wavelength and transmissive of the first wavelength, is situated within the optical cavity between the first reflector and the nonlinear material. In operation, the forward-propagating converted beam is reflected from the second reflector, and then combines with the reverse-propagating converted beam. The angled reflector reflects the combined beam so that it exits from the optical cavity at a nonzero exit angle.

Abstract: A wavelength-selectable laser system (10) is achieved by addressing the suitable mode-locked frequency of a multi-length laser cavity formed by multiple wavelength-selective mirrors (20) such as fiber gratings. This is useful for fiber optic communication and WDM (wavelength division multiplexing) networks where there is incorporated an information encoder/modulator (22) of the light in the sending side and a detector in the receiving side, which are matched to the laser system.

Abstract: A multiplexed medical diode laser system is described that increases power available for applications that require approximately 760 nm or shorter wavelength radiation. Radiation from a diode laser emitter or emitter group is multiplexed with radiation from other diode laser emitters or emitter groups into a single fiber. The diode laser emitters or emitter groups are injected intermittently with current by transistors and thus, a quasi-cw diode laser source particularly useful for PDT is available. Since the radiation is multiplexed, diode laser emitters or emitter groups can be operated at optimal duty factors and generate less thermal energy, thereby increasing efficiency and power output of the system while maintaining at least near cw output. In a preferred embodiment, large peak and average output powers are obtained with a combination of fast switching transistors that regulate the duty factor of diode laser emitters or emitter groups, and suitable optics that multiplex the outputs.

Abstract: A laser oscillation device, which has an optical fiber where laser ion is doped; an excitation emission element that generates one laser beam including multiple wavelength components by exciting the laser ion in the optical fiber by light emission; a total reflection element that is located at one end of the optical fiber and reflects uniformly laser beam with multiple wavelengths; a separation optical element that is located at another end of the optical fiber and separates laser beam into beams with multiple wavelengths; and a plurality of partial reflection element that reflect separately laser beams with multiple wavelengths separated by the separation optical element.