Abstract: The present invention includes a laser amplifier and a method of making the same. The laser amplifier of the present invention includes a gain medium layer having a first index of refraction, and a coupling layer optically coupled to the gain medium. In the various embodiments described herein, the coupling layer can have a second index of refraction less than the first index of refraction. The laser amplifier described herein can also include an evanescent layer disposed between the gain medium and the coupling layer. The evanescent layer can have a third index of refraction less than the second index of refraction. The laser amplifier provides high power, efficient laser resonance through frustrated total internal reflection and total internal reflection while simultaneously providing for the minimization of waste heat in the gain medium layer.

Abstract: Surface emitting laser arrays with intra-cavity harmonic generation are coupled to an optical system that extracts harmonic light in both directions from an intra-cavity nonlinear optical material in such a way that the focusing properties of the light beams are matched.

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: An optical resonator has an internal cavity with an output coupler, an end mirror, and one or more active mirror amplifiers (AMAs) that are arranged in a manner to form a laser radiation propagation path within the cavity which substantially has the form of a star polygon trajectory.

Abstract: A Distributed Bragg Reflector (DBR) that has relatively low light absorption, relatively low electrical resistance, and/or relatively good thermal conductivity. The DBR may include a first mirror layer and a second mirror layer, with an interface therebetween. A step transition is provided in the aluminum concentration and in the doping concentration at or near the interface between the first mirror layer and the second mirror layer. To reduce optical absorption, the interface between the first and second mirror layers may be positioned at or near a null in the optical electric field within the DBR. A graded junction may also be provided. The graded junction may be more lightly doped, have a graded aluminum concentration, and may be placed at or near a peak in the optical electric field.

Abstract: Systems, configurations and methods of using an ultrafast, self-starting, mode-locked laser are provided. The systems, devices and methods of using stable, self-starting mode-locked lasers, can be compact, use fewer optical elements and have energies sufficient for most micro-processing and micro-structuring applications. The large spectral bandwidth of ultra-short (femtosecond) laser pulses can be used in laser sensing applications, micro-machining, time-resolved experiments, where short-lived transient species can be observed in biological or chemical reactions. Terahertz radiation can be generated using ultrashort pulses and used for imaging applications.

Abstract: The subject of the invention is a laser comprising a semiconductor active medium with a population inversion lifetime ?c and a resonant cavity with a lifetime of the photons in the cavity ?p. The cavity includes means for being longitudinally monomode and means so that ?p>?c, such as for example a very long cavity, so as to obtain a laser with a very low intrinsic noise.

Abstract: An external-cavity laser light source apparatus includes a plurality of laser light emission modules, each including a first mirror, a second mirror reflecting fundamental wave light toward the first mirror, a lasing medium emitting the fundamental wave light, a wavelength converter performing wavelength conversion on incident fundamental wave light to produce first converted light and non-converted light. A third mirror reflects second converted light to produce reflected, converted light, the second converted light being wavelength-converted light produced when the non-converted light is reflected off the second mirror and incident again on the wavelength converter. The plurality of modules are disposed so that the first converted light beams exit the modules in the same direction and the reflected, converted light beams exiting the modules approach each other. A deflector may deflect the reflected, converted light beams exiting from the modules in the same exit direction as the first converted light.

Abstract: A distributed feedback semiconductor laser may have (1) a controlled complex-coupling coefficient which is not affected by grating etching depth variation, and (2) facet power asymmetry with no facet reflection which eliminates a random effect of facet grating phase. The device comprises a multiple-quantum-well active region, and a complex-coupled grating formed by periodically etching grooves through a part of the active region. The semiconductor materials for a barrier layer where the groove etching is to be stopped, a regrown layer in the etched groove, and a laser cladding layer, are chosen all the same, so as to form an active grating entirely buried in the same material, providing a complex-coupling coefficient which is defined independently of the etching depth. Facet power symmetry may also be provided by composing the laser cavity of two sections (“front” and “back” sections) having different (“front” and “back”) Bragg wavelengths.

Abstract: A laser chamber is provided that increases power, initiation, and discharge efficiency over single chamber lasers by providing a multi-fold laser chamber, protrusions, discharge segmentation and inversion techniques.

Abstract: A nitride semiconductor laser device includes a nitride semiconductor laser element having a resonator end surface and capable of emitting light with a wavelength of at most 420 nm, a heat sink joined to the nitride semiconductor laser element, a stem with the heat sink mounted thereon, and a light detecting element mounted on the stem for detecting a laser beam from the nitride semiconductor laser element. The nitride semiconductor laser element, the heat sink and the light detecting element are enclosed within a cap that is joined to the stem, and an atmosphere within the cap has a dew point of at most ?30° C. and an oxygen concentration of at most 100 ppm.

Abstract: An external cavity laser apparatus includes a wavelength tuning element mounted to a carrier on the apparatus's platform. Thermal control of the platform sets an initial position of the carrier and tuning element, from which independent tuning of the element can be achieved for wavelength tuning. The carrier is formed of a liquid crystal polymer that thermally isolates the tuning element from this platform, for such independent thermo-optical tuning. The liquid crystal polymer may match the coefficient of thermal expansion of the carrier to that of the platform. The support further includes embedded electrodes, either within or on the outer surface of the carrier, which can couple from the tuning element to the controller, where in some examples such coupling is direct and without use of additional electrical traces or wire bonds.

Abstract: An optically pumped semiconductor-laser (OPS-laser) resonator includes an arrangement for delivering optical pump radiation on an OPS-chip to cause fundamental radiation to circulate in the resonator. The resonator includes second and third-harmonic generating crystals and is arranged deliver third-harmonic radiation. The resonator also includes a stop positioned and configured to stabilize the laser output. The pump radiation arrangement delivers the pump radiation at an angle to the resonator axis and includes wedged GRIN lens arranged such that the pump radiation forms a circular spot on the OPS chip. The third harmonic generating crystal acts as a polarizer for the fundamental radiation and angularly separates fundamental and third harmonic beams.

Abstract: A volume Bragg grating (VBG) has a narrow wavelength. The wavelength is changed by changing an angle of the VBG or a temperature of the VBG. Thus, the present invention has a narrow wavelength, a bright laser, a simple system and an adjustable reflection for a wide application to laser systems.

Abstract: An apparatus for adjusting the wavelength of a laser capable of lasing at multiple wavelengths by using a single acousto-optical modulator and a pair of optical reflectors inside a laser cavity. By adjusting the frequency and amplitude of the radio-frequency source to the acousto-optical modulator, undesired wavelengths are suppressed in the laser cavity, leaving appreciable gain only at the desired wavelength.

Abstract: The invention is directed to elements used in high power laser lithographic systems operating at below 250 nm, and in particular to elements that have a coating of selected materials to extend lifetime of the elements; and to a method of preparing the extended lifetime elements. The invention is particularly directed to gratings and mirrors that are coated with silicon dioxide, aluminum oxide or fluorinated silicon dioxide. The coatings of the invention attain their extended life as a result of being deposited while being simultaneously bombarded with an energetic ion plasma.

Abstract: A distributed feedback (DFB) quantum dot semiconductor laser structure is provided. The DFB quantum dot semi-conductor laser structure includes: a first clad layer formed on a lower electrode; an optical waveguide (WG) formed on the first clad layer; a grating structure layer formed on the optical WG and including a plurality of periodically disposed gratings; a first separate confinement hetero (SCH) layer formed on the grating structure layer; an active layer formed on the first SCH layer and including at least a quantum dot; a second SCH layer formed on the active layer; a second clad layer formed on the second SCH layer; an ohmic layer formed on the second clad layer; and an upper electrode formed on the ohmic layer. Accordingly, an optical WG is disposed on the opposite side of the active layer from the grating structure layer, thereby increasing single optical mode efficiency.

Abstract: A high-power optically end-pumped external-cavity semiconductor laser is provided having a laser chip including an active layer and a distributed Bragg reflector (DBR) for emitting light of a fundamental wavelength; an external mirror spaced apart from a first surface of the laser chip and forming a cavity resonator with the DBR; a second harmonic generation (SHG) crystal positioned between the external mirror and the laser chip; and a micro-lens integrated heat sink dissipating heat generated by the laser chip and bonded to a second surface of the laser chip to focus a pumping beam to be incident on the second surface of the laser chip.

Abstract: The field of the invention is that of solid-state laser gyros. One of the major problems inherent in this technology is that the optical cavity of this type of laser is by its nature highly unstable. To reduce this instability, the invention proposes to introduce controlled optical losses into the cavity that depend on the polarization direction by placing in the cavity an optical assembly comprising a polarizing element, a first element exhibiting a reciprocal effect that acts on the polarization of the wave and a second element exhibiting a nonreciprocal effect that also acts on the polarization of the wave, at least one of these two effects being variable, and to electronically slave these losses to the difference in intensity between the counterpropagating modes. Several devices are described that implement either fixed reciprocal effects combined with variable nonreciprocal effects, or vice versa.

Abstract: An electro-optical system includes a plurality of electromagnetic gain media having a corresponding plurality of apertures. The apertures are disposed in a predetermined spatial distribution. The system further includes at least one refracting surface disposed to intercept energy from the plurality of apertures and a reflecting surface to direct portions of the intercepted energy back through the at least one refracting surface and back toward the plurality of apertures. The return energy is distributed about the plurality of apertures.

Abstract: A structure includes a photonic crystal layer including a first member having a high refractive index in which a plurality of holes are periodically arranged, and a second member having a low refractive index. A third member is disposed on the first member. The third member has a refractive index higher than 1.0 and lower than the refractive index of the first member. The holes of the photonic crystal layer have a depth in the range of 20% to 80% of the thickness of the first member.

Abstract: An optical device, optical system, and method of generating optical beams having high angular momenta are provided. The optical device includes a whispering gallery mode resonator defining a resonator radius and an elongated waveguide having a length defined between a first end and a second end of the waveguide. The waveguide defines a waveguide radius which increases at least along a portion of the length of the waveguide in a direction from the first end to the second end. The waveguide radius at the first end of the waveguide is smaller than the resonator radius and the resonator is integrally formed with the first end of the waveguide.

Abstract: A vertical-cavity, surface-emission-type laser diode includes an optical cavity formed of an active region sandwiched by upper and lower reflectors, wherein the lower reflector is formed of a distributed Bragg reflector and a non-optical recombination elimination layer is provided between an active layer in the active region and the lower reflector.

Abstract: A light source device includes a plurality of light emitting elements for emitting light beams, a resonant mirror functioning as a resonator for selectively reflecting the light beams emitted respectively from the light emitting elements, towards the light emitting elements, a wavelength selection element disposed on light paths between the light emitting elements and the resonant mirror, having a plurality of light selection areas for executing selection respectively on the light beams emitted respectively from the light emitting elements, transmitting light beams each having a part of a wavelength band of corresponding one of the light beams emitted respectively from the light emitting elements, and having a narrower width of a wavelength band of the light beam to be transmitted than a width of wavelength band of the light beam to be reflected by the resonant mirror, and a state changing section that changes a state of the plurality of light selection areas, and the state changing section changes the state

Abstract: A harmonic generation/beam shaping system to generate a shaped beam having a harmonic relationship with a beam generated by a laser, including a first harmonic generation element and a second harmonic generation element arranged sequentially along an axial beam path extending between an input from the laser and an output of the harmonic generation/beam shaping system and at least two beam shaping elements located along the axial beam path. At least one of the least two beam shaping elements is located between the second harmonic generation element and the laser to transform the beam energy profile into a preferred profile to distribute the beam energy across a larger cross sectional area of at least one harmonic generation element or to reduce peaks in the energy distribution profile of the beam, or both, wherein the preferred profile may be a flat-top profile or a Bessel function profile.

Abstract: A structure includes a photonic crystal layer which has a first member having a first refractive index and having a surface with a plurality of holes periodically arranged therein, and includes a low-refractive-index layer adjacent to the photonic crystal layer and having a second refractive index that is lower than the first refractive index. The relative refractive index difference between the first refractive index and the second refractive index is 0.10 or lower. Third members having a third refractive index that is higher than 1.0 are disposed in the holes.

Abstract: An optical parametric oscillator includes a source of coherent energetic pump optical signals and an optical resonator cavity which includes a set of optical parametric amplifying (OPA) crystals and a set of optical elements such as mirrors disposed along an optical path. The optical elements are configured (1) to direct an oscillation optical signal generated by the OPA crystals along the optical path, (2) to provide input coupling of the energetic pump optical signals such that each energetic pump optical signal travels through only one of the OPA crystals to result in a corresponding depleted pump optical signal, and (3) to provide output coupling of the depleted pump optical signals to prevent each depleted pump optical signal from traveling through more than one of the OPA crystals. Resonator cavities have multiple-leg configurations, including “L” and “U” shapes, and either linear (or standing-wave) or ring architectures.

Abstract: To provide surface-emitting type semiconductor lasers that can emit laser light with a high power output and a narrow radiation angle, and methods for manufacturing the same. A surface-emitting type semiconductor laser 200 in accordance with the present invention includes a substrate 101, a first mirror 102 formed above the substrate 101, an active layer 103 formed above the first mirror 102, a second mirror 104 formed above the active layer 103, and a lens section 190 formed above the second mirror 104, wherein the lens section 190 has a function to change a path of light that is emitted from an upper surface 104a of the second mirror 104, at least one of the first mirror 102 and the active layer 103 has a photonic crystal region 122 having a refractive index distribution that is periodic in a plane direction, and the photonic crystal region 122 has a defect region 124 and has a function to confine light in the defect region 124.

Abstract: A laser interferometer mirror assembly (1) comprises a glass base (2) and first and second orthogonal glass mirror blocks (3, 4) each mirror block being supported on an upper surface (5) of the glass base using a pair of feet (6, 7, 8, 9).

Abstract: An optical actuator having an improved response time and an improved frequency operational range due to the reduced mass of a substrate coupled to an actuator and method of making the same. The optical actuator may be formed by adhering an uncoated substrate to the actuator using an epoxy. Once cured, any deformities and irregularities in a top surface of the substrate are removed. An optical coating is then applied to the top surface of the substrate. Once finished, the optical actuator may be used in a laser resonating cavity. Further, the optical actuator desirably may have a resonant frequency of about 150 kHz.

Abstract: A variable light controlling device comprising a substrate, an optical waveguide disposed on the substrate, a first heater and a second heater to change the optical waveguide's temperature is fabricated. And a total amount of the power supplied to the first and the second heater, or a total amount of heat emitted from both of the first and second heater, is maintained substantially constant. Then, the substrate is protected from temperature changes, thereby, stable and quick wavelength tuning operations are realized.

Abstract: In an optical device, a slab layer includes an active layer sandwiched between cladding layers. The slab layer has a periodic refractive index profile structure in a two-dimensional plane, as a two-dimensional slab photonic crystal structure, and a linear defect region serving as a waveguide in the periodic refractive index profile structure. Regions having different widths of the waveguides, as segments of the waveguide, are connected in series.

Abstract: A long wavelength vertical cavity surface emitting laser having a substrate, a first mirror situated on the substrate, an active region situated on the first mirror, a second mirror situated on the active region. The first mirror may have several pairs of layers with an oxidized layer in one or more pairs of that mirror. The substrate may include InP and the mirror components may be compatible with the InP. The one or more layers in the first mirror may be oxidized via a trench-like approach or other arrangement.

Abstract: The invention provides a method and an apparatus for forming a plurality of ultraviolet-wavelength laser beams, and a laser machining apparatus, in which the machining efficiency can be improved due to easy maintenance and inspection while deterioration of wavelength conversion means can be prevented to reduce the running cost. A laser beam with a near infrared wavelength output from a laser oscillator is branched into a plurality of laser beams by a laser distribution unit. Each branched laser beam is partially converted into a laser beam whose wavelength is ½ of the near infrared wavelength by a wavelength converter.

Abstract: A monoblock laser cavity includes a plurality of discrete optical components disposed serially on a substrate and sharing a common optical axis. The optical components include a laser rod of gain material, a Q-switch, an OPO crystal, and an output coupler. The output coupler has at least one convex end face to improve the beam quality.

Abstract: A beam delivery system of a projection exposure system comprises a laser generating a beam of laser light from a plurality of longitudinal laser modes in a cavity, wherein light generated by a single longitudinal laser mode has an average line width ?lat, wherein the laser light of the beam has, at each of respective lateral positions of the beam, a second line width ?lat corresponding to lateral laser modes, and wherein the laser light of the beam has, when averaged over a whole cross section thereof, a line width ?b corresponding to plural lateral laser modes, and wherein ?m<?lat<?b, and wherein an optical delay apparatus disposed in the beam provides an optical path difference ?l, wherein 0.8 · ? 0 2 ( 2 · ? ? ? ? l ) < ? ? ? l < 1.8 · ? 0 2 ( 2 · ? ? ? ? l ) , wherein ?0 is an average wavelength of the light of the first beam of laser light, and ??lat represents the second line width.

Abstract: A line narrowing module includes an elliptical mirror, a diffraction grating disposed at a first focus of the mirror for separating an incident beam into different lines, and a laser beam dispersion and extraction unit. The laser beam dispersion and extraction unit disperses incident laser over the diffraction grating and selectively extract from the resulting lines a laser beam having a desired narrowed bandwidth. A light source that employs the line narrowing module also includes a laser oscillator for generating the beam, and a light returning unit that returns one fraction of the beam extracted from the laser oscillator back to the laser oscillator. Another fraction of the beam is extracted from the laser oscillator through a front window of the laser oscillator, and undergoes line narrowing in the module. The laser beam having the narrowed bandwidth is immediately output as the exposure light from the module.

Abstract: Electro-absorption modulators and methods of making the same are described. In one aspect, an electroabsorption modulator includes first and second electrodes, first and second cladding regions, an active region, and a tunnel junction structure. The first and second cladding regions are between the first and second electrodes. The active region is between the first and second cladding regions and includes a light absorption region. The tunnel junction structure is between the active region and one of the first and second cladding regions.

Abstract: A light emitting device includes a first unit having a first excitation light source including a laser element emitting blue wavelength band excitation light, and a first wavelength converting member including at least one type of fluorescent material and which absorbs at least a portion of a first excitation light, converts the wavelength, and releases light with a wavelength longer than the first excitation light, and a second unit having a second excitation light source including a laser element which emits excitation light with a wavelength band shorter than the blue wavelength band excitation light, and a second wavelength converting member which includes at least one type of fluorescent material and which absorbs at least a portion of a second excitation light, converts the wavelength, and releases light with a wavelength longer than the second excitation light. The first unit and the second unit are combined using a bundle fiber.

Abstract: A laser assembly is suitable for coupling laser light into at least one optical fiber. The laser assembly contains a plurality of laser light sources disposed spaced from a light entrance surface of the at least one optical fiber. The laser light sources are divided into at least one group of first laser light sources and at least one group of second laser light sources. An aperture is provided and is suitable for spatially confining the laser light emitted during operation of the laser light sources before being coupled into the at least one optical fiber. A coupling device is provided and is suitable for coupling the laser light during operation of the first and second laser light sources before it enters into the at least one optical fiber.

Abstract: An unstable optical resonator for an optically active medium comprising a spherical back mirror and a spherical outcoupling mirror is proposed, and an outcoupling which is asymmetrical in relation to the optical axis takes place therein.

Abstract: An optical power control system for a semiconductor source spectroscopy system controls power fluctuations in the tunable signal from the spectroscopy system and thus improves the noise performance of the system. This general solution has advantages relative to other systems that simply detect reference power levels during the scan and then correct the detected signal after interaction with the sample by reducing the requirements for coordinating the operation of the sample detectors and power or reference detectors. The spectroscopy system comprises a semiconductor source and a tunable filter. The combination of the semiconductor source and tunable signal illuminate a sample with a tunable signal, being tunable over a scan band. The power control system comprises an amplitude detector system for detecting the power of the tunable optical signal and power control system for regulating the amplitude of the tunable optical signal in response to its detected power.

Abstract: A linear cavity design to produce a traveling wave operation as in a ring laser without the ring cavity design. All fiber configurations may be used to implement fiber lasers based on the linear cavity design.

Abstract: The invention relates to wavelength-selective optical filters for allowing light of a narrow optical spectral band, centered around a wavelength (?c) to pass through them, while reflecting the wavelengths lying outside this band. According to the invention, the transfer function (T1,2(?)) of the component is defined by multiplying two transfer functions of spectrally offset Fabry-Perot filters.

Abstract: An active layer (18) is formed over a semiconductor substrate having a pair of facets (15A, 15B) mutually facing opposite directions. An upper cladding layer (19) is formed on the active layer, having a refractive index lower than that of the active layer. A diffraction grating (25) is disposed in the upper cladding layer on both sides of a distributed feedback region in a waveguide region (22), the waveguide region extending from one facet to the other of the semiconductor substrate. End regions (22B) are defined at both ends of the waveguide region and the distributed feedback region (22A) is disposed between the end regions. Low refractive index regions (26) are disposed in the upper cladding layer on both sides of each of the end regions of the waveguide region, the low refractive index regions having a refractive index lower than that of the upper cladding layer.

Abstract: The transmittance of an etalon relative to an oscillating line having the wavelength of 1061.6 to 1062.2 nm by an Nd:YAG laser medium 3 is set to 0.9 or lower (the maximum value of the transmittance is 1.0). The oscillating line of the wavelength of 1061.6 to 1062.6 nm is damped by the etalon so that a peak corresponding thereto does not substantially appear in an outputted laser beam. Accordingly, a longitudinal mode can be preferably changed to a single mode and an output can be stabilized.

Abstract: A terahertz (THz) frequency radiation source to emit radiation in a narrow wavelength band within a range of about 3 ?m to 3000 ?m. This source includes: a broad bandwidth emitter to generate a broad bandwidth emitted wavelength band within the wavelength range; a first planar waveguide optically coupled to the broad bandwidth emitter to transmit the broad bandwidth radiation; a disk resonator evanescently coupled to the first planar waveguide with a resonance wavelength band within the emitted wavelength band; and a second planar waveguide evanescently coupled to the disk resonator to transmit radiation in the narrow wavelength band. The emitted wavelength band has a bandwidth greater than or equal to about 0.01 times a mid-band wavelength. The resonance wavelength band has a resonance wavelength bandwidth of less than or equal to about 0.25 times the emitted bandwidth. The narrow wavelength band is substantially equal to the resonance wavelength band.

Abstract: An optical structure comprising an optical resonator is provided. The optical resonator comprises a first set of nested closed optical regions, forming a distributed feedback resonator structure with a direction of radially alternating optical refractive index, and a second set of nested optical regions, forming a distributed feedback resonator structure with a direction of radially alternating optical refractive index. Each optical region of the second set is interrupted by a first gap region with a lower refractive index, wherein the first gap regions substantially overlap in the direction of radially alternating optical refractive index. The first set is arranged nested within the second set and the optical structure further comprises a first optical waveguide optically coupled to the optical resonator via a first waveguide portion reaching into the first gap regions and being arranged coplanar to the optical resonator.

Abstract: A laser apparatus is disclosed. The laser apparatus has a diffraction grating that receives laser light from a semiconductor laser, emits first order diffracted light having a predetermined wavelength to the semiconductor laser, and reflects zero-th order light, a reflection section that reflects the zero-th order light reflected by the diffraction grating, a hold section that holds the diffraction grating and the reflection section while an open angle of the diffraction grating and the reflection section is kept constant, the hold section being rotatable with a fulcrum of an intersection of an extended line of a front surface of the diffraction grating and an extended line of a front surface of the reflection section, and a linear drive section that rotates the hold section with a linear motion of a piezoelectric device that expands and shrinks by the piezoelectric effect.

Abstract: A semiconductor laser includes an active layer on an n-type InP substrate. A diffraction grating and a p-type InP cladding layer are above the active layer. The diffraction grating has at least one phase shift portion. Facets of the distributed feedback laser each have thereon an antireflective film having a reflectance of 3% or less. The diffraction grating does not extend into end regions of the distributed feedback laser, each end region extending 1 ?m-20 ?m from a respective one of the facets toward an opposite end in a waveguide direction.