Abstract: A wavelength calibration system determines an absolute wavelength of a narrowed spectral emission band of an excimer or molecular laser system. The system includes a module including an element which optically interacts with a component of an output beam of the laser within the tunable range of the laser system around the narrowed band. An inter-level resonance is detected by monitoring changes in voltage within the module, or photo-absorption is detected by photodetecting equipment. The absolute wavelength of the narrowed band is precisely determinable when the optical transitions occur and are detected. When the system specifically includes an ArF-excimer laser chamber, the module is preferably a galvatron containing an element that photo-absorbs around 193 nm and the element is preferably a gas or vapor selected from the group consisting of arsenic, carbon, oxygen, iron, gaseous hydrocarbons, halogenized hydrocarbons, carbon-contaminated inert gases, germanium and platinum vapor.

Abstract: Apparatus for transporting a laser-pulse from a pulsed-laser to a receiver includes a pulse-expander, an optical-fiber, and a pulse-compressor. The pulse-expander is arranged to receive and temporally-expand the laser-pulse from the pulsed laser. The optical-fiber at its proximal end to receive the laser-pulse from the pulse-expander and transport the laser-pulse to the pulse-compressor. The pulse-compressor is arranged to receive the laser-pulse from the optical-fiber, temporally-compress the laser-pulse, and deliver the laser-pulse to the receiver. The pulse-compressor includes a block of optically-dispersive material, the temporal-compression being effected by an optical arrangement that causes the laser-pulse to follow a zigzag path through the block of optically-dispersive material. The pulse-expander may be arranged to provide variable third-order dispersion of a laser-pulse being expanded. The pulse compressor may be included in a handpiece attached to the distal end of the optical-fiber.

Abstract: A long wavelength infrared laser system is disclosed where radiation from laser sources such as frequency-doubled Nd:YAG or a Cr:LiSAF is used to resonantly pump a gain medium consisting of a holmium-doped fluoride crystal having a high active ion concentration. The laser pump source has a pulse duration that may be short enough to gain switch a particular transition or long enough to allow end-pumping with high energy densities without damage. The gain material has an absorption approximately resonant with the pump source wavelength, and the dopant concentration is selected to maximize absorption strength for a given excitation. The output radiation from the laser system consists of one or more wavelengths including, in particular 3.9 nm but also other infrared wavelgths such as 1.4 &mgr;m, 2.9 &mgr;m and 3.4 &mgr;m., several of which may be produced simultaneousely from the same laser material through the mechanism of cascade transitions.

Abstract: The invention refers to a laser having first and second reflecting elements (3, 4) defining a laser cavity; a laser microchip (1) provided in the laser cavity to generate laser radiation of a fundamental wavelength; and a quasi-phase matching non-linear optical element (2) provided in the laser cavity to receive said laser radiation of the fundamental wavelength from the laser microchip (1) and to emit frequency doubled laser radiation (SH) of a wavelength half as long as the fundamental wavelength.

Abstract: A narrow band, high power and coherent source of red light in the red (600-650 nm) spectral region is disclosed. The red light source comprises a first optical source for emitting a first light beam at a first wavelength, a second optical source for emitting a second light beam at a second wavelength, a combiner for combining the first and second light beams to produce a combined beam, and a nonlinear crystal responsive to the combined beam for producing a sum frequency light beam of red light.

Abstract: The array is highly suitable for producing a spacially wide output “beam” (comprising a number of individual beams). It suffers less from problems of hotspots and filamentation since each tapered laser supports a limited number of modes, or even a single mode. Therefore it produces a semiconductor laser which is especially suitable for pumping of other lasers and to be used in materials processing.

Abstract: A pulsed laser preferably a tunable laser having a narrow band width is provided which has a high conversion efficiency at a high repetition rate. The laser includes a diffraction grating located in the laser's optical cavity. The optical cavity is defined by a mirror and diffraction grating or two mirrors with a diffraction grating therebetween. A tunable laser material is located within the optical cavity between the mirror and the diffraction grating. Desirably the diffraction grating is movably mounted within the optical cavity so that a beam of a presected wave length diffracted by the grating can be directed across the laser material. Optionally where two mirrors define the optical cavity, one of the mirrors or the grating or both can be movably mounted within the optical cavity. Preferable the movable grating and the movable mirror are rotatably mounted.

Abstract: A laser writing system includes a high reflector and an output coupler that define an oscillator cavity. A gain medium and a mode locking device are positioned in the oscillator cavity. A diode pump source produces a pump beam that is incident on the gain medium and an output beam is produced. A support holds a workpiece. Means are provided for directing the output beam across the workpiece.

Abstract: A multi-pass, integrating diode pump cavity for an Er,Yb:glass laser is provided. The diode pump cavity comprises two end members of undoped glass sandwiching a center section of glass of the same composition as that of the two end members but doped with erbium and ytterbium ions. The two end members are each provided with a curved outer surface, which is coated with a reflective coating. At least one of the curved surfaces includes a slit through the reflective coating for transmission of pump laser light from a pump diode laser bar into the cavity. The diode pump cavity is small, compact, efficient, and eye-safe.

Abstract: A tunable laser incorporating an N1×N2 chirped waveguide grating router that has N1N2 wavelengths, accessible in a digitally rapid manner, and using only N1+N2+1 semiconductor optical amplifiers. Through the use of chirp, free-spectral range of the router can be significantly less than the channel span. The exemplary laser has N1=5, N2=8, a channel spacing of 100 GHz, and the router free-spectral range is only 20 channels.

Abstract: A gas mixture of a gas discharge laser such as an excimer or molecular fluorine laser is stabilized. The gas mixture of the laser includes a constituent halogen containing molecular species such as F2 or HCl which is subject to depletion from an initial optimum concentration. When the gas mixture is energized by a pulsed discharge circuit, the amplified spontaneous emission (ASE) signal is monitored. The status of the gas mixture is determined based on the monitored ASE signal. Stimulated emission is preferably filtered or blocked for more precise ASE signal monitoring. The gas mixture is preferably replenished using small halogen injections, total pressure adjustments and mini and partial gas replacements based on the evolving gas mixture status determined from the monitored ASE signal.

Abstract: A technique of stabalizing during operation a gas mixture with a gas composition initially provided within a discharge chamber of an excimer or molecular fluorine gas discharge laser includes monitoring a temporal pulse shape of the laser beam and adjusting and/or determining the status of the gas mixture based on the monitored temporal pulse shape. The monitored temporal pulse shape is preferably compared with a reference temporal pulse shape. The difference or deviation between the monitored temporal pulse shape and a reference temporal pulse shape is calculated. The amount of and intervals between gas replenishment actions are determined based on the calculated deviation. The energy of the beam is also monitored and the driving voltage and gas actions are adjusted to stabilize the energy, energy stability and/or energy dose.

Abstract: An F2 laser having an etalon-based line narrowing output coupler and a technique for tuning the laser. The etalon based output coupler is adjusted to preferentially reflect a percentage of light at or near the spectral maximum of one of the primary F2 spectral lines and to not reflect light at the other primary F2 spectral line. Thus, a selected range of the selected line is preferentially amplified in the gain medium and the other line is transmitted out of the laser cavity and, therefore, receives no amplification and is suppressed. The result is substantial narrowing in the preferred embodiment of the 157.630 nm line and effective suppression of the 157.523 nm line. Substantial improvement in line narrowing of 157.630 nm line results from a wavelength selective properties of etalon based line-narrowing output coupler.

Abstract: A high pulse rate pulse power source for supplying controlled high energy electrical pulses at rates of 2000 Hz or greater. The source includes a pulse generating circuit including a charging capacitor, a solid state switch and a current limiting inductor. Pulses generated in the pulse generating circuit are compressed in at least two pulse compression circuits and a step-up pulse transformer increases peak voltage to at least 12,000 volts. A very fast regulated power supply is provided for charging the charging capacitor in less than 400 microseconds and a pulse control system including a programmed processor controls the charging of the charging capacitor to an accuracy of less than about one percent at a rate of at least 4000 charges per second. In a preferred embodiment capable of operating at pulse rates of 2000 to 4000 Hz or greater, water cooling of the saturable inductors is provided.

Abstract: A pumping circuit for a semiconductor laser is formed by connecting a semiconductor laser in series with a positive temperature coefficient (PTC) thermistor element which has a temperature coefficient in the range between −1.5%/° C. and −0.5%/° C. within the temperature range between −20° C. and +70° C. and of which the temperature coefficient becomes positive at a temperature over +70° C. A resistor insensitive to temperature changes may be further connected to the PTC thermistor element either in series or in parallel. The semiconductor laser and the PTC thermistor element are disposed sufficiently close to each other so as to be thermally coupled inside a container such as a can to form a semiconductor apparatus.

Abstract: A method for temperature compensating an optical filter utilizes information relating to the temperature coefficient/constant of the optical filter to identify a value for the feedback resistor in a transimpedance preamplifier contained in a laser control system. Changes or effects in transmission resulting from temperature changes in the optical filter can be compensated by selecting a feedback resistor or resistors having a temperature dependence value and corresponding sign and magnitude to offset the undesirable effects on the transmission resulting from temperature tuning of a laser and thereby varying the temperature dependencies of the optical filter in the signal path.

Abstract: The module has a planar platform. A straight light guide is formed on the planar platform for guiding incoming light and outgoing light. A filter is interposed slantingly in the light guide for reflecting a part of light propagating in the light guide but for allowing the rest of the light to pass through. An LD or LED is mounted at an extension of the light guide for producing sending signal light and introducing the sending light into the light guide. A photodiode is mounted on the platform at a point on a path of the reflected light for sensing the incoming (receiving signal) light. Guide pins are fixed to the platform for attaching to and detaching from an optical connector having holes and an optical fiber. In the attached state, the end of the light guide of the module faces the end of the fiber in the connector.

Abstract: Apparatus for simultaneously monitoring and controlling the wavelength of a plurality of semiconductor lasers whose wavelengths can be adjusted, the device including a wavelength filter including a wavelength division demultiplexer (WDM) arranged to receive a portion of the output power of each laser and divide the laser output between two filter outputs, a photoreceiver arranged to measure the power at each filter output, a processor arranged to selectably compute the ratio of the power at the two filter outputs for each laser, apparatus to compare the computed ratio with a predetermined reference ratio for the selected laser, and apparatus to adjust the wavelength of the selected laser in response to the comparison.

Abstract: The free spectral range dependent on the length of an oscillator is put in a relation of integral times with respect to the free spectral range dependent on the length of at least a nonlinear optical crystal or a wavelength selection SHG output element. Thereby, reduced noise in the output of a second-harmonic generator is intended.

Abstract: A monitoring and control assembly for an optical system includes a tunable laser. The laser generates a divergent output beam along an optical axis. A first photodetector is provided. A wavelength selective filter is tilted at an angle relative to the optical axis that provides an angular dependence of a wavelength reflection of the wavelength selective filter and directs the reflected output beam towards the first photodetector.