Abstract: An Environmentally stable optical fiber mode-locked laser generating device having an achromatic quarter wave plate is disclosed. An optical fiber unit is formed of a polarization maintaining (PM) optical fiber, and a Bragg grating is formed on a first region from one end in direction to the other end, a gain material is doped on a core of a remaining second region. An optical coupling unit provides a pump laser input to one end of the optical fiber unit, and outputs a laser input from the optical fiber unit. A lens unit converts a laser output from the other end of the optical fiber unit and focuses the laser on a certain regime.

Abstract: In one embodiment, a multilayer dielectric coating for use in an alkali laser includes two or more alternating layers of high and low refractive index materials, wherein an innermost layer includes a thicker, >500 nm, and dense, >97% of theoretical, layer of at least one of: alumina, zirconia, and hafnia for protecting subsequent layers of the two or more alternating layers of high and low index dielectric materials from alkali attack. In another embodiment, a method for forming an alkali resistant coating includes forming a first oxide material above a substrate and forming a second oxide material above the first oxide material to form a multilayer dielectric coating, wherein the second oxide material is on a side of the multilayer dielectric coating for contacting an alkali.

Abstract: A resonator mounting assembly includes a resonator cage, a base underlying the resonator cage, a plurality of first sets of kinematic mounting elements with the kinematic mounting elements of each first set mated with one another in an engaged non-secured relationship so as to support the resonator cage above the base and provide a kinematic mounting interface between them that substantially prevents any rotational moments applied on the base to be transferred to the resonator cage, and at least one second set of preload mounting elements fastened with one another in a yieldable secured relationship so as to preload the resonator cage relative to the base to maintain a positive contact at the kinematic mounting interface that substantially prevents disengagement of the mated kinematic mounting elements from one another due to forces and moments generated from thermal expansion and mounting distortion of the base.

Abstract: The present invention relates to a device for controlling optical frequency (F1, F2) about a central working frequency (F0). This device comprises a vertical cavity (2) formed of two parallel and partially reflecting walls (3a, 3b), and a membrane (6) comprising at least one layer (7a, 7b) structured in the form of a photonic crystal. In this device, the two walls (3a, 3b) are separated by an optical distance substantially proportional to half the wavelength (?0) corresponding to the central working frequency (F0). The membrane (6) is integrated between the walls (3a, 3b) of the cavity (2) and devised in such a way as to exhibit a mode of optical resonance at this central working wavelength (?0). At least one layer of the device is made up of at least one portion of a material exhibiting nonlinear optical properties.

Abstract: A CO2 gas laser device according to the present invention amplifies CO2 laser light that oscillates repeatedly in short pulses having a pulse width of 100 ns or less, and cools a CO2 laser gas which is excited by continuous discharge by circulating the CO2 laser gas by means of forced convection. Therein, an angle ? defined by the optical axis of the amplified CO2 laser beam and the flow direction of the CO2 laser gas caused by the forced convection is determined by both a discharge cross sectional area and a discharge length of a volume in which the CO2 laser gas is excited by discharge, whereby increasing the gain of pulsed laser to achieve pulsed laser light having an extremely high average output power.

Abstract: Methods, systems and apparatus are disclosed for delivery of pulsed treatment radiation by employing a pump radiation source generating picosecond pulses at a first wavelength, and a frequency-shifting resonator having a lasing medium and resonant cavity configured to receive the picosecond pulses from the pump source at the first wavelength and to emit radiation at a second wavelength in response thereto, wherein the resonant cavity of the frequency-shifting resonator has a round trip time shorter than the duration of the picosecond pulses generated by the pump radiation source. Methods, systems and apparatus are also disclosed for providing beam uniformity and a sub-harmonic resonator.

Abstract: A laser (12, 18) with a laser resonator (13), the laser resonator (13) having a non-linear optical loop mirror (1, 1?), NOLM, which is adapted to guide counter-propagating portions of laser pulses, and to bring the counter-propagating portions of laser pulses into interference with each other at an exit point (4) of the NOLM (1, 1?). The non-linear optical loop mirror (1, 1?) has a non-reciprocal optical element (7, 7?).

Abstract: A spatially modulated waveguide Bragg grating mirror is suspended over a substrate by plurality of fingers extending laterally away from the waveguide centerline. The positions of the fingers are coordinated with the positions of crests and valleys of amplitude or phase modulation of the Bragg grating, to avoid disturbing the Bragg grating when it is tuned by heating. When the Bragg grating is heated, the heat flows through the fingers creating a quasi-periodic refractive index variation along the Bragg grating due to quasi-periodic temperature variation created by the heat flow from the grating through the supporting fingers. Due to coordination of the positions of supporting fingers with positions of the crests and valleys of modulation, the optical phase coherence is maintained along the Bragg grating, so that the spectral lineshape or filtering property of the Bragg grating is substantially preserved.

Abstract: A laser apparatus may include: a first module including an oscillator configured to output a laser beam and an oscillator support portion for supporting the oscillator; a second module including a beam delivery unit for delivering the laser beam and a beam delivery unit support portion for supporting the beam delivery unit; a third module including an amplifier for amplifying the laser beam and an amplifier support portion for supporting the amplifier; and a frame on which the modules are placed, the frame including mounts on which the oscillator support portion, the beam delivery support portion and the amplifier support portion are placed.

Abstract: A method and apparatus for stabilizing the seed laser in a laser produced plasma (LPP) extreme ultraviolet (EUV) light system are disclosed. In one embodiment, the cavity length of the laser may be adjusted by means of a movable mirror forming one end of the cavity. The time delay from the release of an output pulse to the lasing threshold next being reached is measured at different mirror positions, and a mirror position selected which results in a cavity mode being aligned with the gain peak of the laser, thus producing a minimum time delay from an output pulse of the laser to the next lasing threshold. A Q-switch in the laser allows for pre-lasing and thus jitter-free timing of output pulses. Feedback loops keep the laser output at maximum gain and efficiency, and the attenuation and timing at a desired operating point.

Abstract: A laser system includes a semiconductor laser having a laser driver coupled thereto. An output of the semiconductor laser is optically coupled to an input of an optical splitter that provides outputs including or coupled to a first branch having a first branch fiber coupled to a feedback reflector which provides a cavity boundary that defines a passive secondary cavity for the semiconductor laser, and a second branch including a back reflection reduction device. The roundtrip attenuation from an output facet of the laser to the feedback reflector is from ?30 dB to ?80 dB. The laser driver provides sufficient drive stability so that a frequency variation of the semiconductor laser is less than one free spectral range (FSR) of the secondary cavity. An output of said system is taken after the back reflection reduction device.

Abstract: Mid-IR supercontinuum laser source in the 3-12 micron region generating at least tens of watts of optical power and based on non-silica optical fiber pumped by a ZBLAN fiber laser generating light at about 2.7 microns. The zero-dispersion wavelength of the non-silica fiber substantially coincides with the lasing wavelength. The proportion of the SC output above 3 microns exceeds 40 percent of the overall power output.

Abstract: A lighting apparatus for retrofitting an existing luminaire includes a plurality of light emitting diodes (LED) of similar or differing wavelengths arranged and configured in at least one light bar array, a heat sink module thermally coupled to the at least one light bar array, an electronic power module electrically coupled to the at least one light bar array, and a plate coupled to the at least one light bar array, electronic power module and the heat sink module, the plate arranged and configured for coupling to the luminaire to provide quick and easy installation and replacement of the at least one light bar array, heat sink module and electronic power module into and from the luminaire.

Abstract: A method and device for emitting electromagnetic radiation using semipolar or nonpolar gallium containing substrates is described where the backside of the substrate includes multiple scribes that reduce stray light leaking.

Abstract: An ultrashort-pulse laser that has a resonator that includes a laser gain medium, dispersion compensation optics, and a deformable optical element adapted to change its shape and consequently one or more characteristics of pulses output from the cavity.

Abstract: A pulse fiber laser device 1 has a Fabry-Perot type optical resonator, and is provided with an excitation light source 11, an optical coupling unit 12, an amplifying optical fiber 13, a saturable absorber 14, a gradient index lens 15, an optical output unit 16, a dispersion adjusting unit 17, a mirror 21 and a mirror 22. The saturable absorber 14 and the mirror 21, integrated into one body, constitute a saturable absorber mirror 23. The gradient index lens 15 converges the light output from an end face of an optical fiber 32 and outputs the light to the saturable absorber mirror 23, and inputs the light reflected from the saturable absorber mirror 23 into the end face of the optical fiber 32. Thus, there is provided a pulse fiber laser device that enables easy adjustment of the intensity of light incident on a saturable absorber and facilitates miniaturization.

Abstract: To improve a laser system comprising at least one externally stabilizable semiconductor laser, from the laser active zone of which a laser radiation field can be coupled out, and a feedback element, disposed externally in the laser radiation field, which couples out, from the laser radiation field, a feedback radiation field having a defined wavelength and bandwidth, and couples back same into the active laser zone for determining the wavelength and bandwidth of the laser radiation field, in such a way that the wavelength stabilization may be achieved more cost-effectively, it is proposed that the feedback element is a resonant waveguide grating which reflects back a portion of the laser radiation field lying within an angular acceptance range.

Abstract: An optical coherence analysis system comprising: a first swept source that generates a first optical signal that is tuned over a first spectral scan band, a second swept source that generates a second optical signal that is tuned over a second spectral scan band, a combiner for combining the first optical signal and the second optical signal for form a combined optical signal, an interferometer for dividing the combined optical signal between a reference arm leading to a reference reflector and a sample arm leading to a sample, and a detector system for detecting an interference signal generated from the combined optical signal from the reference arm and from the sample arm. In embodiments, the swept sources are tunable lasers that have shared laser cavities.

Abstract: An optical amplifier suitable for coherently amplifying surface plasmon-polariton waves with high gain and low noise over visible and infrared wavelengths. The optical amplifier is comprised of a thin strip of material having a complex permittivity with a negative real part, in contact on at least one side with an optical gain medium, where the strip has finite width and thickness such that optical radiation couples to the strip and propagates along its length as a surface plasmon-polariton wave. The surface plasmon-polariton amplifier can also be incorporated into a resonant cavity to form a plasmon-polariton laser.

Abstract: Dry oxygen, dry air, or other gases such as ozone are hermetically sealed within the package of the external cavity laser or ASE swept source to avoid packaging-induced failure or PIF. PIF due to hydrocarbon breakdown at optical interfaces with high power densities is believed to occur at the SLED and/or SOA facets as well as the tunable Fabry-Perot reflector/filter elements and/or output fiber. Because the laser is an external cavity tunable laser and the configuration of the ASE swept sources, the power output can be low while the internal power at surfaces can be high leading to PIF at output powers much lower than the 50 mW.

Abstract: A swept wavelength light source is provided, the light source includes a semiconductor gain device operable to provide amplification, an optical retarding device, the retarding device having a block of material, a beam path with a well-defined beam path length being defined for light within the block of material produced by the gain device, a wavelength selector, and the gain device, the retarding device and wavelength selector being mutually arranged on the base so that a resonator is established for light portions emitted by the gain device and selected by wavelength selector; this does not exclude the presence of further elements contributing to the resonator, such as additional mirrors (including resonator end mirrors), lenses, polarization selective elements, other passive optical components, etc.; wherein the beam path in the retarding device is a part of a beam path of the resonator.

Abstract: This disclosure is directed to widen an adjustable range of the spectral linewidth of laser light output from a laser apparatus. This laser apparatus may include: (1) an excitation source configured to excite a laser medium in a laser gain space, (2) an optical resonator including an output coupler arranged on one side of an optical path through the laser gain space and a wavelength dispersion element arranged on the other side of the optical path through the laser gain space, and (3) a switching mechanism configured to switch a beam-width magnification or reduction factor by placing or removing at least one beam-width change optical system for expanding or reducing a beam width in or from an optical path between the laser gain space and the wavelength dispersion element or by inverting orientation of the at least one beam-width change optical system in the optical path.

Abstract: A laser amplifier system is provided which comprises a resonator with optical resonator elements which determine a course of a resonator radiation field which propagates along an optical axis and at least one laser-active medium (LM). The resonator is designed as a split resonator and has a first resonator section which extends from a first virtual plane of separation and a second resonator section which extends from a second virtual plane of separation. The resonator sections are dimensioned optically such that the resonator radiation field has radiation field states corresponding to the same resonator modes in each of the virtual planes of separation. An amplifying unit optically independent of the resonator is arranged between the first and the second virtual planes of separation. The amplifying unit comprises the at least one laser-active medium and couples the radiation field states in a neutral manner with respect to the resonator modes.

Abstract: In one embodiment, the invention relates to systems, methods and devices for improving the operation of an electromagnetic radiation source or component thereof. In one embodiment, the source is a laser source. A Fourier domain mode locked laser can be used in various embodiments. The sources described herein can be used in an optical coherence tomography (OCT) system such as a frequency domain OCT system. In one embodiment, laser coherence length is increased by compensating for dispersion. A frequency shifter can also be used in one embodiment to compensate for a tunable filter induced Doppler shift.

Abstract: A laser apparatus may include a first laser light source configured to emit light with a first wavelength, a second laser light source including a titanium-sapphire laser device and a plurality of wavelength conversion elements and being configured to emit light with a second wavelength being one-fourth of a wavelength of light emitted from the titanium-sapphire laser device, and a wavelength conversion element configured in such a manner that the light with the first wavelength and the light with the second wavelength are incident thereon to emit light with a wavelength of about 193 nm corresponding to a sub frequency of the light with the first wavelength and the light with the second wavelength.

Abstract: An external-cavity one-dimensional multi-wavelength beam combiner that performs wavelength beam combining along a stacking dimension of a laser stack formed of a plurality of laser arrays, each laser array configured to generate optical radiation having a unique wavelength, and each of the plurality of laser arrays including one or more laser emitters arranged along an array dimension of the laser stack. The multi-wavelength beam combiner includes an optical imaging element configured to image each of the laser emitters along a slow axis of the laser emitters, an optical focusing element arranged to intercept the optical radiation from each of the plurality of laser arrays and combine the optical radiation along a stacking dimension of the laser stack to form a multi-wavelength optical beam, and a diffraction element positioned at a region of overlap of the optical radiation to receive and transmit the multi-wavelength optical beam.

Abstract: A method of generating intra-resonator laser light (1) comprises the steps of coupling input laser light (2), e.g.

Abstract: A composite optical waveguide 1 includes a first optical waveguide 9 comprising a silica-based core and a second optical waveguide 11 comprising an Si-based core. The second optical waveguide 11 is joined to the first optical waveguide 9. The length of the first optical waveguide 9 corresponds to a permissible propagation loss of the second optical waveguide 11. The second optical waveguide 11 includes a sharply curved portion 13 having a radius smaller than the minimum bend radius of the first optical waveguide 9.

Abstract: A monoblock laser cavity incorporates optical components for a short-pulse laser. These optical components are ‘locked’ into alignment forming an optical laser cavity for flash lamp or diode laser pumping. The optical laser cavity does not need optical alignment after it is fabricated, increasing the brightness of the monoblock laser.

Abstract: A laser diode element assembly includes: a laser diode element; and a light reflector, in which the laser diode element includes (a) a laminate structure body configured by laminating, in order, a first compound semiconductor layer of a first conductivity type made of a GaN-based compound semiconductor, a third compound semiconductor layer made of a GaN-based compound semiconductor and including a light emission region, and a second compound semiconductor layer of a second conductivity type made of a GaN-based compound semiconductor, the second conductivity type being different from the first conductivity type, (b) a second electrode formed on the second compound semiconductor layer, and (c) a first electrode electrically connected to the first compound semiconductor layer, the laminate structure body includes a ridge stripe structure, and a minimum width Wmin and a maximum width Wmax of the ridge stripe structure satisfy 1<Wmax/Wmin<3.3 or 6?Wmax/Wmin?13.3.

Abstract: This invention relates to semiconductor laser apparatus with a structure for reducing the divergence angle of output light and for narrowing the spectral width. The semiconductor laser apparatus has at least a semiconductor laser array, a collimator lens, a path rotator, and an optical element with a reflecting function. The collimator lens collimates a plurality of laser beams from the semiconductor laser array, in a predetermined direction. The path rotator outputs each beam collimated in the predetermined direction, with a predetermined divergence angle in the predetermined direction in a state in which a transverse section of the beam is rotated by about 90°. The optical element is arranged at a position where at least a part of each beam from the path rotator arrives, and constitutes at least a part of an external resonator. This optical element reflects a part of each beam from the path rotator to return the reflected part of each beam to the active layer in the semiconductor laser array.

Abstract: A device representing a reflector, for example, an evanescent reflector or a multilayer interference reflector with at least one reflectivity stopband is disclosed. A medium with means of generating optical gain is introduced into the layer or several layers of the reflector. The optical gain spectrum preferably overlaps with the spectral range of the reflectivity stopband. This device can be attached to air, semiconductor or dielectric material or multilayer structures and provide a tool for preferential amplification of the optical waves propagating at larger angles with respect to the interface with the evanescent or the multilayer interference reflector. Thus angle selective amplification or generation of light is possible. Several evanescent or interference reflectors can be used to serve the goal of preferable amplification the said optical waves.

Abstract: An external cavity laser assembly (10) that generates a light beam (12) includes a gain medium (14) and a diffraction grating (24). The gain medium (14) has a growth direction (14C), a fast axis (14A), a first facet (34A), and a second facet (34B) that is spaced apart from the first facet (34A). The gain medium (14) emits from both facets (34A) (34B). Further, a beam polarization (30) of the light beam (32) emitting from the second facet (34B) is perpendicular to the growth direction (14C) and the fast axis (14A). The grating (24) includes a plurality of grating ridges (24A) that are oriented parallel to the beam polarization (30). Moreover, each of the grating ridges (24A) can have a substantially rectangular shaped cross-sectional profile.

Abstract: According to one embodiment, the present application includes a tunable laser configured in a small package. The tunable laser includes a housing with a volume formed by exterior walls. An electrical input interface is positioned at the first end of the housing and configured to receive an information-containing electrical signal. An optical output interface is positioned at the second end of the housing and configured to transmit a continuous wave optical beam. A tunable semiconductor laser is positioned in the interior space and operable to emit a laser beam having a selectable wavelength. A focusing lens assembly is positioned in the interior space along an optical path of the laser beam to operatively couple the laser beam to the optical output interface.

Abstract: In the case of a lens array type homogenizer optical system, the incident angle and intensity of a laser beam 1 entering a large-sized lens (long-axis condenser lens 22) of a long-axis condensing optical system, which is provided on the rear side, are changed for every shot by performing laser irradiation while long-axis lens arrays 20a and 20b are reciprocated in a direction corresponding to a long axial direction of a linear beam (X-direction). Therefore, vertical stripes are significantly reduced. Further, the incident angle and intensity of a laser beam 1 entering a large-sized lens (projection lens 30) of a short-axis condensing optical system, which is provided on the rear side, are changed for every shot by performing laser irradiation while short-axis lens arrays 26a and 26b are reciprocated in a direction corresponding to a short axial direction of a linear beam (Y-direction). Therefore, horizontal stripes are significantly reduced.

Abstract: The invention relates to a laser (1) for emitting laser light in the visible spectral range. A rare earth doped anisotropic crystal (2) comprising a 5d-4f transition is arranged within a laser resonator (7, 8), and a pumping light source (3) pumps the crystal (2) for generating laser light in the visible spectral range by using the 5d-4f transition. The 5d-4f transition of the rare earth doped anisotropic crystal comprises an absorption band extending over several nm. Thus, pump light having a wavelength within a relatively broad wavelength range can be used. This reduces the requirements with respect to the wavelength accuracy of the pumping light source and, thus, more pumping light sources of an amount of produced pumping light sources can be used for assembling the laser, thereby reducing the amount of rejects.

Abstract: A surface emitting semiconductor laser includes a substrate, an n-type lower DBR, an n-type cavity extending region formed on the lower DBR, an active region formed on the cavity extending region, and an upper DBR formed on the active region. A difference in refractive index between a relatively high refractive index layer and a relatively low refractive in the upper DBR is smaller than that in the lower DBR.

Abstract: The invention relates to a laser light source for generating narrow-band laser radiation with high coherence, comprising a laser diode (1), which forms an internal resonator (4), and an external resonator (7) coupled to the internal resonator (4). The object of the invention is to improve a laser source of the kind such that it generates narrow-band and coherent laser radiation with high output power and at the same time with high long-term stability. Furthermore, the laser light source is to be produced in a cost-effective manner. The object is achieved by the invention in that the laser diode (1) runs in an operating mode in which multimode laser radiation is generated, comprising a plurality of spectrally neighboring resonance modes (9) of the external resonator (7). The resonance modes are selected by adapting the spectral characteristics of the external (7) and internal (4) resonators.

Abstract: An electromagnetically responsive element includes sets of arrangements of self-resonant bodies, such as atoms or quantum dots that form an effective dielectric constant, typically at or near a resonance.

Abstract: An electromagnetically responsive element includes sets of arrangements of self-resonant bodies, such as atoms or quantum dots that form an effective dielectric constant, typically at or near a resonance.

Abstract: A tilted wave semiconductor diode laser containing additional structural elements that improve beam quality is provided. The tilted wave laser includes a narrow active waveguide coupled to a broad passive waveguide, and light generated in the active waveguide leaks to the broad waveguide and propagates in it in the form of a tilted optical wave. The device emits laser light coming out from the broad waveguide in the form of one or two narrow beams. The additional structural elements may include grooves intersecting the narrow waveguide and a stripe that suppress undesired emission from the narrow waveguide; grooves that extend parallel to the stripe that suppress parasitic lateral optical modes; unpumped sections of the stripe that suppress light emission from the narrow waveguide; and facet coatings having distinct reflectance for the light in the narrow and in the broad waveguides thus suppressing emission of light from the narrow waveguide.

Abstract: A system and method for addition of broad-area semiconductor laser diode arrays are described. The system can include an array of laser diodes, a V-shaped external cavity, and grating systems to provide feedback for phase-locking of the laser diode array. A V-shaped mirror used to couple the laser diode emissions along two optical paths can be a V-shaped prism mirror, a V-shaped stepped mirror or include multiple V-shaped micro-mirrors. The V-shaped external cavity can be a ring cavity. The system can include an external injection laser to further improve coherence and phase-locking.

Abstract: A device having a light cavity includes, at one end, a plasmonic reflector having a grating surface for coupling incoming light into traverse plasmon waves and for coupling the traverse plasmon wave into broaden light, the surface serving to redistribute light within the cavity, the reflector being well suited for use in laser diodes for redistributing filamental cavity laser light into spatially broaden cavity laser light for translating multimodal laser light into unimodal laser light for improved reliability and uniform laser beam creation.

Abstract: A control system for improving and stabilizing Fourier domain mode locking (FDML) operation. The control system may also provide regulation of FDML operational parameters such as filter tuning, laser gain, polarization, polarization chromaticity, elliptical polarization retardance, and/or dispersion. The control system may be located internal to or external from the FDML laser cavity.

Abstract: A laser resonator and method for forming the laser resonator are provided. The method comprises placing a housing for the laser resonator in an alignment fixture, attaching a bond plate to an optical component of the laser resonator, attaching a first end of an alignment arm to the bond plate attached to the optical component, attaching a second end of the alignment arm to the alignment fixture such that the optical component is disposed over the housing, aligning, via the alignment fixture and the alignment arm, the optical component relative to the housing, and bonding the aligned optical component to the housing. The first end of the alignment arm may removed once the aligned optical component is bonded to the housing.

Abstract: An optical amplifier suitable for coherently amplifying surface plasmon-polariton waves with high gain and low noise over visible and infrared wavelengths. The optical amplifier is comprised of a thin strip of material having a complex permittivity with a negative real part, in contact on at least one side with an optical gain medium, where the strip has finite width and thickness such that optical radiation couples to the strip and propagates along its length as a surface plasmon-polariton wave. The surface plasmon-polariton amplifier can also be incorporated into a resonant cavity to form a plasmon-polariton laser.

Abstract: A method of manufacturing a semiconductor laser having an end surface window structure includes the steps of forming a groove near at least the formation position of the end surface window structure of a substrate, and growing a nitride-based group III-V compound semiconductor layer including an active layer formed of a nitride-based group III-V compound semiconductor including at least In and Ga on the substrate.

Abstract: A lighting apparatus for retrofitting an existing luminaire includes a plurality of light emitting diodes (LED) of similar or differing wavelengths arranged and configured in at least one light bar array, a heat sink module thermally coupled to the at least one light bar array, an electronic power module electrically coupled to the at least one light bar array, and a plate coupled to the at least one light bar array, electronic power module and the heat sink module, the plate arranged and configured for coupling to the luminaire to provide quick and easy installation and replacement of the at least one light bar array, heat sink module and electronic power module into and from the luminaire.

Abstract: A method and apparatus is disclosed for operating a laser output light beam pulse line narrowing mechanism that may comprise a nominal center wavelength and bandwidth selection optic; a static wavefront compensation mechanism shaping the curvature of the selection optic; an active wavefront compensation mechanism shaping the curvature of the selection optic and operating independently of the static wavefront compensation mechanism. The method and apparatus may comprise the nominal center wavelength and bandwidth selection optic comprises a grating; the static wavefront compensation mechanism applies a pre-selected bending moment to the grating; the active wavefront compensation mechanism applies a separate selected bending moment to the grating responsive to the control of a bending moment controller based on bandwidth feedback from a bandwidth monitor monitoring the bandwidth of the laser output light beam pulses. The active wavefront compensation mechanism may comprise a pneumatic drive mechanism.

Abstract: Laser light wavelength control is provided by periodically predicting a next position of a light controlling prism using a model of the prism's motion characteristics. The prediction is then updated if a measurement of laser output wavelength is obtained. However, because the predictions are made without waiting for a measurement, they can be made more frequently than the laser firing repetition rate and the prism can be repositioned at discrete points in time which can occur more frequently than the laser firing events. This also reduces performance degradation which may be caused by being one pulse behind a laser measurement and the resultant laser control signal being applied.