Abstract: A laser annealing apparatus has a laser generating section for producing a laser beam, a splitter arranged to partially reflect and partially transmit the laser beam. The apparatus has a first energy converting section for measuring the energy value of the laser beam reflected from the splitter and outputting it into an electrical signal and has an energy control section for comparing the output signal of the first energy converting section to a reference value and automatically correcting the energy value by the difference between them. A process window may be positioned so the laser beam can pass through a built-in slit for annelaing a substrate. The apparatus further has a second energy converting section for measuring the energy value of the laser beam passing through the process window. In response to the output of the second energy converting section, the energy control section corrects the energy intensity of the laser beam.

Abstract: A system for making small signal gain measurements of a chemical laser, such as an HF or DF laser. The system is adapted to measure the two dimensional (x,y) gain distribution in real time (i.e. 30 to 40 frames per second). The system includes a resonating galvanometer driven scanning mirror which is able to tilt in both the horizontal x and vertical y direction. The scanning mirror is used for scanning the gain profile of an HF/DF probe laser. The tiltable scanning mirror with appropriate optics, allows the laser beam from the probe laser to be scanned while remaining parallel to the nozzle exit plane of the laser and thus allows the two dimensional scanning of the gain distribution in real time (i.e. at rates up to 40 frames per second). As such, the system is adapted to be controlled by a personal computer with the data stored on a hard disk drive therewithin.

Abstract: An excimer laser with optical pulse multiplication produced by separating a laser beam into a plurality of beams and multiplying the pulse rate in each beam. A pulse multiplier optical system receives the laser output beam and produces multiple output beams, each beam having a larger number of pulses with substantially reduced intensity values as compared to the laser output beam. In a preferred embodiment, CaF2 flats are used along with maximum reflection mirrors to split the laser beam into four beams each with a 4× increased pulse rate. The present invention is particularly important as an improvement to the ArF excimer laser industry to reduce two-photon absorption damage to optical equipment in lithography machines.

Abstract: Embodiments of the invention include an optical fiber laser system with a cascaded Raman resonator (CRR) or other suitable Raman frequency shifting device having a length of optical fiber with at least one input pump reflector, a series of Raman-Stokes order reflectors and an output reflector therein. The reflectors are written to provide sufficient conversion efficiency despite the use of the cascaded Raman resonator with differing pump laser wavelengths. The reflectors are written not necessarily in correspondence with the gain maxima of the intermediate Stokes orders, but instead are written to reflect with less than maximum gain conversion intensity, yet in a manner that allows different pump laser wavelengths to be converted thereby. When operating the cascaded Raman resonators at sufficiently high pump powers, input pump reflectors are not necessary. Cascaded Raman resonators designed in accordance with embodiments of the invention are useful with different pump laser wavelengths.

Abstract: A passively cooled solid-state laser system for producing high-output power is set forth. The system includes an optics bench assembly containing a laser head assembly which generates a high-power laser beam. A laser medium heat sink assembly is positioned in thermal communication with the laser medium for conductively dissipating waste heat and controlling the temperature of the laser medium. A diode array heat sink assembly is positioned in thermal communication with the laser diode array assembly for conductively dissipating waste heat and controlling the temperature of the laser diode array assembly. The heat sink assemblies include heat exchangers with extending surfaces in intimate contact with phase change material. When the laser system is operating, the phase change material transitions from solid to liquid phase.

Abstract: The present invention, in one form, is an imaging system which, in one embodiment, utilizes a filter assembly including a plurality of filter portions for altering the intensity and quality of an x-ray beam. Specifically, in one embodiment, by positioning the filter assembly so that the x-ray beam is filtered by the first portion of the filter assembly, the x-ray beam is altered to perform a body portion scan. By positioning the filter assembly to the second portion, the x-ray beam is altered to perform a head portion scan.

Abstract: A visible light alignment system mounted on a line narrowing module of a UV laser. The system includes an alignment platform on which a small visible light laser is mounted and beam directing optics to direct the visible light beam to reflect off an illumination surface of a first prism in a prism beam expander at an angle such that the visible light beam proceeds collinearly with the UV laser output beam.

Abstract: A wavelength stabilized laser system includes a laser that produces a laser light. The laser light has an amplitude and a wavelength that vary with the laser temperature. A first detector provides a first signal representing the amplitude of the laser light. A filter has a gain that is a function of the wavelength of the laser light. The filter receives the laser light and outputs a filtered light having an amplitude that varies with the wavelength of the laser light. A second detector provides a second signal representing the amplitude of the filtered light. A transformer has a primary and a secondary. The primary is electrically coupled to the first and second detectors. The primary of the transformer includes a first coil connected to the first detector and a second coil connected to the second detector. The first and second coils of the primary are opposite in polarity from each other.

Abstract: A fiber laser or fiber amplifier uses resonant pumping of the gain medium by providing a pump resonator that establishes a resonator cavity at the pump wavelength which includes the pumped gain medium. The pump resonator may be of a distributed feedback (DFB) or a distributed Bragg reflector (DBR) type construction, and may be combined with signal reflection apparatus of either DFB or DBR type construction that provides oscillation of the desired laser output wavelength. If used without a signal reflection apparatus, the invention may be operated as a resonant pumped fiber amplifier. A resonant pumped laser may use a wavelength stabilized pump source to maximize pumping efficiency, the stabilization being provided by optical feedback.

Abstract: An optical transmitter providing the benefits of both filter-locked and wavelength-locked lasers is disclosed by modifying an external cavity (32) for the integration of an optical modulator (14). The external cavity (32) provides a round-trip path for light travel. A substrate (24) is connected to the external cavity (32) where at least one gain element (16) and the optical modulator (14) are integral with the substrate (24). A partial reflector (40) is also integral with the substrate (24) and couples the at least one gain element (16) with the optical modulator (14).

Abstract: A method for controlling the emitting-wavelength of a diode-laser or diode-laser array in a diode-laser pumped solid-state laser (DPSS-laser) is disclosed. The DPSS-laser can be controlled, in a light-control mode, to provide constant output-power. Alternatively, the DPSS-laser can be controlled such that a constant current is supplied to the diode-laser. In the light-control mode, diode-laser temperature is periodically varied by a small temperature increment above and below a set temperature, and the diode-laser current required to provide constant DPSS-laser output-power is monitored. A difference in diode-laser current at temperatures higher and lower than the set temperature indicates that the emitting-wavelength of the diode-laser has changed from an optimum value. Changing the diode-laser set temperature to a value at which there is no difference in current at the higher and lower temperatures restores the emitting-wavelength of the diode-laser to the optimum value.

Abstract: In a laser diode driving method, a bias current set about the light emission threshold current of a laser diode, and a pulse current for causing the laser diode to emit light are adjusted in accordance with the ambient temperature. The laser diode is driven by a current prepared by superposing the bias current and the pulse current, thereby controlling the optical output and extinction ratio of the laser diode at a constant level. A laser diode driving circuit is also disclosed.

Abstract: Ring and linear cavity, fiber optic laser systems are disclosed, employing non-invasive fiber optic amplification technology. A channel overlay waveguide is employed for amplification of optical energy evanescently coupled to the overlay waveguide from the fiber optic. One of two amplification methods can be employed. The first involves inducing stimulated emission with the overlay waveguide and the second uses a second order, non-linear frequency conversion to down-convert a high-power, short-wavelength pump signal into the waveguide to amplify the optical energy coupled thereto. Amplification of optical energy in the channel overlay waveguide can be established within a single beat length of evanescent removal to evanescent return of the optical energy to the fiber optic. Intra-cavity elements can be employed to effect, e.g., wavelength selection, optical isolation, or modulation of the resultant, optical signal propagating in the fiber optic.

Abstract: A laser resonator is described, with a first and a second end mirror and with coaxial electrodes between which laser radiation reflected back and forth in the direction of an axis of symmetry of the laser resonator passes azimuthally segment by segment through a resonator volume with an annular cross section. The invention is distinguished in that the second end mirror is a substantially conical mirror that deflects the laser radiation striking it to respective azimuthally opposite regions of the resonator volume.

Abstract: A semiconductor laser includes a semiconductor substrate of a first conductivity type and having a front surface; a first semiconductor layer disposed on the front surface of the semiconductor substrate and having a refractive index that increases with distance from the semiconductor substrate; an active layer disposed on the first semiconductor layer; and a second semiconductor layer disposed on the active layer, having a refractive index that decreases with distance from the active layer, and having a ridge. In this laser, the refractive index distribution between the ridge and the substrate is asymmetrical about the active layer so that the center of the intensity of light generated in the semiconductor laser distribution shifts from the active layer toward the substrate, in the direction perpendicular to the front surface of the substrate.

Abstract: In a wavelength multiplexing light source used in an optical wavelength division multiplexing (WDM) transmission system and the like, at least three semiconductor lasers of single longitudinal mode have oscillation frequencies outside of their pull-in range at a normal injection locking without a modulation side band, an output light of a first semiconductor laser is injected in one way into a second semiconductor laser having an oscillation frequency adjacent to that of the first o semiconductor laser through a first one-way optical injection means to generate a modulation side band. The output light of the second semiconductor laser is then injected in one way into a third semiconductor laser having an oscillation frequency adjacent to that of the second semiconductor laser through a second one-way optical injection means to generate the modulation side band for an injection locking.

Abstract: The present invention discloses a method for eliminating, or at least minimizing, the locking range variability of laser modules which employ external grating, such as fiber bragg gratings. It has been observed that the coupling efficiency between the laser and its output fiber is a highly variable property of the laser module, causing variations in the laser module's locking range. The laser module's locking range, however, can be readily reset to or near its nominal value by measuring the laser module's coupling efficiency, and then judiciously choosing a grating having a peak reflectivity which compensates for variations in the coupling efficiency by maintaining constant the effective reflectivity Reff of the fiber/grating combination.

Abstract: A method and article for monitoring and controlling power drift in the output of a diode array is described. The diode array is used, for example, as a light pump for a fiber laser. In one embodiment, an improved fiber laser includes the light pump, which launches light into a laser cavity. The fiber laser further includes a sampler operable to receive at least a portion of the light before it is launched into the laser cavity. The sampled portion represents a known fraction of the total light signal generated by the light pump. In some embodiments, the sampled light is directed, via the sampler, to a photodetector. The photodetector converts the sampled light into a first electrical signal and delivers it to a processor. The processor is operable to compare the electrical signal with a set-point signal representative of a desired power output of the sampled portion of the launched light.

Abstract: A laser oscillator which allows the length of a light guide path between itself and a laser beam machine to be reduced. This laser oscillator comprises a laser resonator and a reflector for reflecting and turning back a laser beam emitted from the laser resonator. The laser beam emitted from an output mirror of the laser resonator is outputted from the laser oscillator after being turned back by the reflector and traveling for a predetermined optical path length. In some cases, the direction of the laser beam outputted from the laser oscillator is opposite to the direction of the laser beam emitted from the output mirror. One of the additional reflectors may be a phase lag reflector, and the laser beam can be converted into a circular polarized beam in the laser oscillator.

Abstract: A generator for producing a low-noise, high-frequency signal has a monomode first laser connected via an optical isolator to a second laser so as to permit light generated by the fist laser to be injected into the second laser. The difference in the frequencies of the lasers and the intensity of the injected light is selected so as to prevent the second laser from locking onto the free-running frequency of the first laser.