Abstract: At least either of the light entering plane or the light exiting plane is parallel to the (111) crystal face of the CaF2 crystal and the laser beam entering from the entering plane passes through the plane located between the [111] axis and the first azimuth axis in the locus of rotation of the [001] axis around the [111] axis and including the [111] axis and the first azimuth axis, the plane located between the [111] axis and the second azimuth axis in the locus of rotation of the [010] axis around the [111] axis and including the [111] axis and the second azimuth axis or the plane located between the [111] axis and the third azimuth axis in the locus of rotation of the [100] axis around the [111] axis and including the [111] axis and the third azimuth axis and exits from the exiting plane.

Abstract: An apparatus and method which may comprise a seed laser defining an optical cavity producing an output. An amplifier may amplify the seed laser output. A bandwidth error signal generator may provide a bandwidth error signal from measured bandwidth and a target. A bandwidth selection element, which may comprise an adjustable sized aperture external to the cavity of the seed laser may selectively alter the bandwidth of the seed laser output. A bandwidth control system may control the bandwidth control element and also selectively adjust a differential firing time between the seed laser and amplifier or another bandwidth selection actuator to cooperated (coarsely or finely) with the bandwidth selection element to control bandwidth of the laser system.

Abstract: A process and a device is described to avoid the depolarization of linear-polarized light during the transmission of light through crystals exhibiting a {111} or {100} crystal plane, respectively, and a <100> or <111> crystal axis, respectively. The device is characterized in that the linear-polarized light meets the surface of the crystals in an angle of 45-75°, whereby the surface is formed by the {111} or the {100} plane. The crystal is arranged in such a way that upon entering the crystal, the light spreads along the <100> or <111> crystal axis, respectively, as parallel as possible, and/or that the device comprises a unit for temperature equalization to avoid a thermal gradient in the crystal.

Abstract: A cap 25 having a piece of glass 26 formed at a laser irradiating position and covering a laser irradiating direction and an upper face of a package 24, is mounted onto the package 24 having lateral faces of a frame body 30 formed in three directions other than the laser irradiating direction, so as to reduce the distance between a semiconductor element 22 and the piece of glass 26 and to reduce a radius 32 of the piece of glass 26. The profile of the semiconductor device can be therefore lowered while maintaining the characteristics of a semiconductor laser. In addition, by mounting the semiconductor device, the profile of an optical pickup device can also be lowered.

Abstract: An apparatus for analyzing, identifying or imaging an target including an integrated dual laser module coupled to a pair of photoconductive switches to produce cw signals in the range of frequencies from 100 GHz to over 2 THz focused on and transmitted through or reflected from the target; and a detector for acquiring spectral information from signals received from the target and using a multi-spectral homodyne process to generate an electrical signal representative of some characteristics of the target with resolution less than 250 MHz. The photoconductive switches are activated by laser beams from the dual laser module. The lasers in the module are tuned to different frequencies and have two distinct low frequency identification tones respectively that are used in conjunction with a stable optical filter element to permit precise determination of the offset frequency of the lasers.

Abstract: Disclosed is a laser system that comprises a laser source adapted to emit a laser beam, wherein the laser source comprises a plurality of emitters for emitting respective beam contributions to the emitted laser beam; and first and second feedback means adapted to provide optical feedback to respective first and second parts of the emitted laser beam. The first feedback means is adapted to predominantly feed back a respective angular/directional contribution of each of said beam contributions into a corresponding one of the plurality of emitters from which said angular/directional contribution was emitted at a predetermined output angle, to cause each of the plurality of emitters to predominantly emit a beam contribution towards the second feedback means at an angle corresponding to the predetermined output angle.

Abstract: For performing hologram recording or reproduction, an oscillation wavelength half value width ?? of a coherent light source satisfies a relationship of ??<?2/(S×2 sin ?), where a substantial hologram size is S, a substantial cross angle between reference light and signal light is ?, and the oscillation wavelength of the coherent light source is ?. Even when stray light is generated, the coherent light source can suppress generation of an unnecessary interference fringe due to the stray light, and stably record and reproduce holograms.

Abstract: A color-mixing laser module is disclosed, which is comprised of a laser unit capable of emitting red, blue and green laser beams; a beam combiner, for receiving and converging the laser beams emitted from the laser unit and then directing the converged laser light to illuminate on a light pattern adjusting unit; and the light pattern adjusting unit, capable of receiving the converged laser light from the beam combiner for adjusting the pattern of the same.

Abstract: The invention relates to laser system with a laser source and an articulated arm. The articulated arm has an optical arrangement for guiding a laser beam from the laser source along an optical path in the articulated arm to a target location. Within the optical path at least one crossing area (focus or focal point) of the laser beam is provided. The optical arrangement has at least one optical cell with an input window and an output window for passing the laser beam therethrough, wherein the crossing area is positioned within the optical cell. The optical cell has a gas fill with an energy threshold for ionization that is increased in comparison to that of ambient air.

Abstract: The present invention relates to a laser projection system (1) having means for reducing the coherence of a generated laser beam (3) in order to reduce the occurrence of annoying speckle artifacts in images produced by the system. Coherence is reduced by letting the laser beam (3) pass through a transparent cell (6) comprising first (A) and second (B) immiscible fluids having different refractive indices. The fluids are displaced in the cell, preferably using an electrowetting technique. The cell (6) may thus be realized as an electrowetting lens, which is driven with a pseudo random driving signal.

Abstract: The present invention discloses a two-light flux interference exposure device comprising: a laser light source provided in a laser resonator; a single harmonic generation device provided in the laser resonator for converting laser light output by the laser light source to higher harmonics; an etalon provided in the laser resonator so as to serve as a narrowband wavelength filter; a beam splitter dividing laser light output outside the laser resonator into two light fluxes; and an interference optic system causing the light fluxes to interfere with each other on a target to be exposed.

Abstract: A laser system including an optical cable jumper with input and output terminals, and a laser gun, wherein the optical jumper transmits a laser beam from a bundle-type optical cable connected to an input terminal thereof to a single-type optical cable connected to an output terminal thereof. The laser gun is connected to the single-type optical cable at a rear of the optical cable jumper to illuminate the laser beam to a target object.

Abstract: An external cavity type semiconductor laser that has a larger output and a more excellent single mode characteristic than a conventional external cavity type semiconductor laser is provided. The external cavity type semiconductor laser has a laser diode 11, a window glass 16, a grating, and a lens. The external cavity type semiconductor laser has several modifications over the conventional one. A first modification is that the window glass 16 is inclined to a beam emission surface 19 of a laser diode 11 for a predetermined angle. A second modification is that arrangements of the laser diode 11 and so forth are adjusted so that a S wave reaches the grating. A third modification is that when an output power of the laser diode 11 is 45 mW or less, a kink is suppressed.

Abstract: An apparatus and method for reducing speckle of a laser beam is disclosed. The apparatus includes a light guide, a highly reflective mirror at the input face of the light guide and a partially-transmissive display after the exit face of the light guide. A coherent laser beam is introduced into the light guide through a clear aperture in the highly reflective mirror. Within the light guide, the laser beam gets separated into plural, successive beamlets having different phase shifts, different polarization states and/or path length differences equal to or greater than the coherence length of the laser beam. The beamlets exit through the partially-transmissive display to provide output laser light with reduced speckle. The light guide can be either a solid light pipe of transmissive material or a hollow tunnel with reflective interior sidewalls.

Abstract: Double Bragg grating scanner receivers (DBS) and methods thereof based on spinning high-efficiency transmitting or reflecting holograms in photo-thermo-refractive (PTRG) glass provides unlimited field of view while incident angle for all components do not exceed approximately 45 degrees. The devices and methods are highly tolerable to high power laser radiation and has no restriction for the use in any laser systems working in visible and near IR spectral regions. Rate of scanning by DBS is higher compared to known mechanical scanners because the use of thin glass plates with recorded holograms and spinning instead of rocking. The components described herein are holographic optical devices (reflecting and transmitting volume gratings) for visible and near IR spectral regions with absolute diffraction efficiency exceeding approximately 95% and high thermal, optical and mechanical stability.

Abstract: A surface light emitting semiconductor laser element, comprises a substrate, a lower reflector including a semiconductor multi-layer disposed on the substrate, an active layer disposed on the lower reflector, an upper reflector including a semiconductor multi-layer disposed on the active layer, a compound semiconductor layer having a first opening for exposing the upper reflector and extending over the upper reflector, and a metal film having a second opening for exposing the upper reflector disposed inside of the first opening and extending over the compound semiconductor layer, wherein the metal film and the compound semiconductor layer constitute a complex refractive index distribution structure where a complex refractive index is changed from the center of the second opening towards the outside. A method of emitting laser light in a single-peak transverse mode is also provided.

Abstract: At least either of the light entering plane or the light exiting plane is parallel to the (111) crystal face of the CaF2 crystal and the laser beam entering from the entering plane passes through the plane located between the [111] axis and the first azimuth axis in the locus of rotation of the [001] axis around the [111] axis and including the [111] axis and the first azimuth axis, the plane located between the [111] axis and the second azimuth axis in the locus of rotation of the [010] axis around the [111] axis and including the [111] axis and the second azimuth axis or the plane located between the [111] axis and the third azimuth axis in the locus of rotation of the [100] axis around the [111] axis and including the [111] axis and the third azimuth axis and exits from the exiting plane.

Abstract: A compact optical system is provided for delivering laser radiation with high optical efficiency and uniformity. The optical system includes, in order of the propagation of light, an expander for producing a collimated beam, a beam shaper including a flat window with a diffraction pattern on one side for transforming the collimated beam into a square top-hat output beam, a corrector for bending the square top-hat output beam back to a system axis, a scan head to scan the square top-hat output beam across the substrate, and a scan lens to image the beam at the substrate plane.

Abstract: A semiconductor laser device includes a semiconductor laser body including a resonator and having a front end face and a rear end face facing each other, the resonator being located between the front end face and the rear end face. The front end face emits principal laser light. A reflectance control film is disposed on the front end face or the rear end face of the semiconductor laser body and is made up of either an aluminum oxide film or a five-layer film including the aluminum oxide film disposed such that it is the layer in the five-layer film farthest from the front end face or the rear end face. A silicon oxide film is disposed on the aluminum oxide film of the reflectance control film and has a thickness of 20 nm or less.

Abstract: The present invention relates to an optical mask at low cost and so on having a structure capable of reducing further a peak of beam intensity caused by diffraction. The optical mask is constructed by overlapping a first mask and a second mask. The first mask and second mask each are a serrated aperture mask. The schematic shapes of the respective apertures of the first mask and second mask are almost rectangular and identical to each other. The fringe defining the aperture of the first mask is machined in a serrated shape, and the fringe defining the aperture of the second mask also is machined in a serrated shape. In the optical mask, the first mask and second mask are overlapped so that the serrations of the fringes defining the respective apertures of the first mask and second mask are located alternately.

Abstract: Certain example embodiments of this invention relate to waveguide lasers (e.g., RF-excited waveguide lasers). Certain example embodiments of this invention provide an optical mounting scheme for use with a waveguide laser. In certain example embodiments, a carrier including an optic holder may be provided. An optic may be mounted to the carrier via a face-sealing epoxy. An optic interface may be formed at least in part by the epoxy. The optic interface may be a thin layer of a substantially uniform thickness located between the carrier and optic face. The carrier and/or the optic holder of the carrier may be beveled proximate to where the optic interface is formed and, optionally, proximate to where the epoxy is applied. In certain example embodiments, the epoxy may be applied to only the optic's face and/or to the optic holder's face.

Abstract: To provide surface-emitting type semiconductor lasers and methods of manufacturing the same in which the polarization direction of laser light can be readily controlled, a surface-emitting type semiconductor laser includes a vertical resonator above a substrate. The vertical resonator includes a first mirror, an active layer and a second mirror disposed in this order from the substrate. The vertical resonator has a plurality of unit resonators. An emission region of each of the unit resonators has a diameter that oscillates in a single-mode.

Abstract: A gas laser includes an unstable laser resonator disposed in a laser housing, and a beam guide configured to guide a laser beam decoupled from the laser resonator out of the laser housing. The laser beam is coupled into the beam guide, and the beam guide is an optical fiber that extends out of the laser housing and guides the beam from the housing.

Abstract: Cavity lasers exhibit a relatively high beam quality (e.g., M2<1.25) despite a relatively small cavity length (e.g., 50-53 mm) for a high (e.g., ?10 watt) output power device. This enables the construction of physically smaller laser and optical assemblies without sacrificing performance. Reduction of optical photonic interference, which can impair imaging performance, is also facilitated. Laser and optical assemblies may utilize an aperture defined within an optical barrier element to reduce the divergence of the light beam emanating from a diode-pumping laser.

Abstract: A package for a laser diode component is described. This comprises a carrier, which has on a front side a mounting region for a laser diode chip or laser diode bar, and at least one holding device, which is arranged on the carrier and has at least one aperture, in which an electrical terminal conductor is held. The holding device is designed for surface mounting. Moreover, a laser diode component with such a package and a method for producing a laser diode component are described. In the method, preferably a plurality of carriers are provided together in an interconnected assembly and are loaded with laser diodes. Subsequently, holding devices each with at least one electrical terminal conductor are fitted on the carriers.

Abstract: A vertical-cavity surface-emitting laser (VCSEL) comprising a low-loss thin metal contact and current spreading layer within the optical cavity that provides for improved ohmic contact and lateral current distribution, a substrate including a plano-concave optical cavity, a (Ga,In,Al)N multiple quantum well (MQW) active region contained within the optical cavity that generates light when injected by an electrical current, and an integrated micromirror fabricated onto the substrate that provides for optical mode control of the light generated by the active region. A relatively simple process is used to fabricate the VCSEL.

Abstract: A multimode fiber optical fiber transmission system includes an improved configuration for launching a single mode long wavelength transmission signal into existing multimode optical fiber networks. More specifically, the invention utilizes new single mode long wavelength VCSEL devices to realize a novel transmitter/transceiver for multimode fiber links where offset launch with controlled mode conditioning is achieved without the use of a mode conditioning patchcord, and in some embodiments, without the use of any collecting or focusing elements.

Abstract: A laser gain material module may include a lasing portion and a perimetral portion. The perimetral portion may be formed in a predetermined shape to substantially prevent any spontaneously emitted photons created in the lasing portion and entering the perimetral portion from returning to the lasing portion.

Abstract: A laser apparatus comprises a laser generating unit, and an intensity pattern regulating unit including a pair of blocking parts and a pair of semi-through parts, wherein the pair of semi-through parts are placed between the pair of blocking parts and adjust an intensity of an incident laser beam.

Abstract: In one embodiment, a lens structure has an object surface, an image surface, and an axicon mirror. The axicon mirror is defined by an inner diameter, an outer diameter, and a tilt angle, with the tilt angle being defined by a plane of the axicon mirror and the surface of the axicon mirror. The image surface is positioned within the inner diameter of the axicon mirror. The lens structure may be incorporated into an optical transmitter having a light source and a photodetector. The light source is positioned to transmit light toward the object surface of the lens structure, and the photodetector is positioned to receive light reflected from the axicon mirror. A method for producing lens structures with different optical attenuation properties is also disclosed.

Abstract: Laser diodes are formed with an outcoupling grating between two separate distributed Bragg reflectors. The devices have gain regions located between the reflector gratings for pumping the active region. The outcoupling grating couples light out of the waveguide normal to the surface if the grating spacings are equal to an integer number of wavelengths of the light within the cavity. If the gratings are not such an integer number, the light is coupled out of the cavity off the normal.

Abstract: The invention relates to laser system with a laser source and an articulated arm. The articulated arm has an optical arrangement for guiding a laser beam from the laser source along an optical path in the articulated arm to a target location. Within the optical path at least one crossing area (focus or focal point) of the laser beam is provided. The optical arrangement has at least one optical cell with an input window and an output window for passing the laser beam therethrough, wherein the crossing area is positioned within the optical cell. The optical cell has a gas fill with an energy threshold for ionization that is increased in comparison to that of ambient air.

Abstract: In an optical signal transmission system which can perform high-speed optical transmission not lower than 1 Gbps, VCSEL has light-emission points. A core diameter of an optical fiber GI-POF is set to not lower than 200 ?m, and the light-emission points of VCSEL are arranged inside an outer periphery at an end face of GI-POF. A polymerization composition material constituting the core of GI-POF is made of a compound containing deuterated poly methacrylic ester. A wavelength of the light beam of VCSEL is set to the range of 770 nm to 810 nm.

Abstract: According to the present invention, a first p-side electrode 7A made of metal which is provided with regularly arranged holes 10 having a diameter smaller than a laser oscillation wavelength and a second p-side electrode 7B arranged around the periphery of the first p-type electrode 7A are used as a p-side mirror of a surface-emitting laser. Light in a resonator formed of a p-side electrode 7 and an n-type mirror 2 is first converted to a surface plasmon and then reconverted to the light by the p-side electrode 7A, and then emitted outside the resonator.

Abstract: A transmitter unit is described for an open path gas detector. The unit comprises: an enclosure having a window; and a coherent radiation transmitter, e.g. a tuneable laser diode transmitter, located within the enclosure and configured to direct a beam of radiation through the window. The window is slanted with respect to the axis of the beam emitted by the transmitter such that no radiation from the transmitter that is directly incident on the window is reflected by the window directly onto the transmitter. Thereby interference fringes within the emitted radiation are reduced. Alternatively, the window may be replaced by a lens followed by an aperture such that the beam emitted by the transmitter is focused onto the aperture, thereby forming a beam of radiation passing out of the enclosure.

Abstract: A tunable laser comprising: a foundation including a first side and an oppositely facing second side and including a hole extending from the first side to the second side; a tuning assembly including a base, a fine tuning arm and a rotational flex bearing disposed adjacent the first side of the foundation; wherein the base is disposed adjacent to the first side of the foundation; wherein one end of the flex bearing is secured to the base; wherein the other end of the flex bearing is secured to the fine tuning arm; wherein a portion of the fine tuning arm extends at least partially into the hole; an external cavity laser including a gain medium, a dispersion medium and a reflective member disposed adjacent to the second side of the foundation; wherein the gain medium and the dispersion medium grating are secured in a fixed relation relative to the each other; wherein the reflective member is secured to the portion of the arm extending into the hole; and a piezoelectric device with one end secured to the base a

Abstract: The present invention discloses a two-light flux interference exposure device comprising: a laser light source provided in a laser resonator; a single harmonic generation device provided in the laser resonator for converting laser light output by the laser light source to higher harmonics; an etalon provided in the laser resonator so as to serve as a narrowband wavelength filter; a beam splitter dividing laser light output outside the laser resonator into two light fluxes; and an interference optic system causing the light fluxes to interfere with each other on a target to be exposed.

Abstract: A surface emitting semiconductor laser includes a laminate of semiconductor layers emitting multimode laser light, and a block member blocking light of a specific mode among the multimode laser light emitted from the laminate.

Abstract: A tunable semiconductor laser includes gain medium, wavelength-selective element and a laser mode matching element. The wavelength-selective element comprises a first light absorbing plate operatively coupled to the laser mode matching element and provided with an array of high reflectivity mirrors as well as a second light absorbing plate with an array of narrow band pass filter mirrors operatively coupled to the high reflectivity mirror array of the first plate. The narrow band pass filter mirror array is disposed over a respective array of apertures in the second plate. The wavelength-selective element also comprises a light reflective plate with an array of retroreflectors and a third light absorbing plate with an array of apertures operatively disposed between the aperture array of the second plate and the retroreflector array.

Abstract: A window assembly for a pressurized laser discharge chamber is disclosed and may include a housing that is formed with a recess. The assembly may also include an optic having a first side that is exposed to chamber pressure and an opposed second side, and a compliant member that may be positioned in the recess to space the second side of the optic from the housing under normal chamber operating pressures. For the assembly, the compliant member may be compressible to allow the optic to mechanically abut the assembly housing during a chamber overpressure.

Abstract: The present invention is directed to a novel arrangement of optical devices for the rapid patterning of laser profiles used for desorption and/or ionization sources in analytical mass spectrometry. Specifically, the new optical arrangement provides for a user-defined laser pattern at the sample target that can be quickly changed (on a microsecond timescale) to different dimensions (or shapes) for subsequent laser firings.

Abstract: This disclosure concerns devices such as DBRs, one example of which includes at least one first mirror layers having an oxidized region extending from an edge of the DBR to an oxide termination edge that is situated greater than a first distance from the edge of the DBR. The DBR also includes at least one second mirror layer having an oxidized region extending from the edge of the DBR to an oxide termination edge that is situated less than a second distance from the edge of the DBR, such that the first distance is greater than the second distance. Additionally, a first mirror layer includes an oxidizable material at a concentration that is higher than the concentration of the oxidizable material in any of the second mirror layers. Finally, a first mirror layer is doped with an impurity at a higher level than one of the second mirror layers.

Abstract: A multimode fiber optical fiber transmission system includes an improved configuration for launching a single mode long wavelength transmission signal into existing multimode optical fiber networks. More specifically, the invention utilizes new single mode long wavelength VCSEL devices to realize a novel transmitter/transceiver for multimode fiber links where offset launch with controlled mode conditioning is achieved without the use of a mode conditioning patchcord, and in some embodiments, without the use of any collecting or focusing elements.

Abstract: A spatial filter adapted to increase the angular spread of non-conjugated energy in a beam and suppress this energy to improve the efficiency of a phase conjugate system. In the illustrative embodiment, the filter includes first and second lenses and an aberrator to increase the angular spread. In the specific embodiment, an opaque plate, with a pinhole aperture therethrough, is sandwiched between the lenses to suppress the non-conjugated energy. The aberrator may be implemented with an amplifier or other suitable mechanism. Likewise, the aperture may be replaced with a highly angle-selective thick Bragg grating or other suitable arrangement. A phase conjugate master oscillator/power amplifier laser architecture is also disclosed.

Abstract: A laser beam delivery system is disclosed, which allows transmission of high-power infrared light through a hollow core photonic band gap (HC-PBG) fiber made of non-silica-based glass. In this system, the infrared beam first passes through input coupling optics which focus the beam onto the hollow core of the HC-PBG fiber. In front of the input end of the HC-PBG fiber, there is provided a mask with a hole aligned with the hollow core, and the infrared beam first passes through this hole before entering the hollow core of the HC-PBG fiber. This protects the photonic band gap structure from being damaged by the beam. After passing through the HC-PBG fiber, which may be from one to several hundred meters in length, the infrared beam exits at the output end of the fiber and passes through output coupling optics which collimate and focus the beam onto a desired target.

Abstract: Using lateral physical modulation, the optical properties of VCSELs can be stabilized and controlled by spatially varying the characteristics of the device material. This results in stabilization of the linewidth, the numerical aperture, the near and far field, as a function of bias and temperature. A VCSEL includes a substrate, an active region sandwiched between an upper and lower distributed Bragg reflector (DBRs), and electrical contacts. A light emission property e.g. the index of refraction, may be varied by patterning or texturing the surface of the substrate prior to growth of the epitaxial DBR layers or at least one layer of either the upper or lower DBRs, or by inserting a non-planar layer.

Abstract: The present invention is a wavelength conversion laser apparatus for converting wavelength by utilizing a nonlinear optical crystal and capable of safely using it over a long time. For this end, the fundamental wave laser light emitted from the pumping chamber unit 3 which is a solid state laser light source is converted into the second harmonic wave by the first nonlinear optical crystal unit 20. And the second harmonic wave is, then, converted into the third (or fourth) harmonic wave by the second nonlinear optical crystal unit 30. Filled in the container 24, 35 for each of the nonlinear optical crystal units 20, 30 is a dry inert gas. A humidity sensor 51 detects humidity inside the container. The output from the humidity sensor 51 is supplied to the laser control portion 58. When the detected humidity exceeds a predetermined value, the laser oscillation is interrupted, thereby preventing the nonlinear optical crystal from being damaged in case of any defect in the sealing structure of the container.

Abstract: A method and apparatus for improving the beam quality of the emissions from a multimode gain medium such as a broad-stripe laser through the use of SBC techniques is provided. In order to achieve the desired beam quality without a significant reduction in output power, discrete lasing regions are formed across the gain medium using an etalon or similar device located within the SBC cavity.

Abstract: A partially mirrored beam tap for use in wavelength and power monitoring, wherein the partially mirrored beam tap splits off at least two beams from an elliptical Gaussian output beam, wherein a first split-off beam is transmitted to an etalon and one or more first photo-detectors for wavelength monitoring, while a second split-off beam is transmitted to one or more second photo-detectors as a reference and for power monitoring. The partially mirrored beam tap splits off the first and second split-off beams from upper and lower tails of the output beam, wherein upper and lower portions of the partially mirrored beam tap comprise mirrored surfaces that reflect tails of the output beam and a center portion of the partially mirrored beam tap comprises a clear rectangular aperture that passes the output beam.

Abstract: Accordingly, a method of suppressing energy spikes is provided comprising projecting a laser beam through a mask having a slit pattern comprising a corner region with edges, and a blocking feature with the corner region to reduce energy spikes projected on a substrate. An alternative method is provided, wherein the corner region is modified such that it is replaced by a more tapered shaped region, preferably a triangle. Also provided, are a variety of mask designs incorporating both corner regions, with and without one or more blocking features, and triangular regions, with or without one or more blocking features. The mask designs provide examples of mask modifications that may be used to reduce energy spikes.