Abstract: A compact semiconductor laser light source providing short wavelength (ultraviolet, blue or green) coherent light by means of frequency doubling of red or infrared light from a high power diode heterostructure. The high power diode heterostructure is a MOPA device having a single mode laser oscillator followed by a multimode, preferably flared, optical power amplifier. A tunable configuration having an external rear reflector grating could also be used. A lens could be integrated with the MOPA to laterally collimate the light before it is emitted. Straight or curved, surface emitting gratings could also be incorporated. An astigmatism-correcting lens system having at least one cylindrical lens surface is disposed in the path of the output from the MOPA to provide a beam with substantially equal lateral and transverse beam width dimensions and beam divergence angles. A nonlinear optical crystal or waveguide is placed in the path of the astigmatism-free symmetrized beam to double the frequency of the light.

Abstract: A phase conjugation mirror (20) for use in a phase conjugation resonator (1). The phase conjugation mirror provides a nonlinear resonance enhancement for a coherent optical signal incident thereon. The phase conjugation mirror is comprised of a semiconductor material having a characteristic bandgap energy selected to be at an absorption bandgap edge, or slightly greater than the absorption bandgap edge, for the coherent optical signal.

Abstract: An apparatus for wavelength conversion of laser light which can prevent optical destruction of a wavelength conversion element and achieve a high wavelength conversion efficiency. The apparatus for wavelength conversion of laser light has an optical focusing system for focusing the input laser light on the wavelength conversion element in an optical cavity, which optical focusing system makes the cross-sectional shape of a light beam non-circular, for example, elliptical.

Abstract: A tunable laser is described in which the gain element is fabricated to produce wavelength dispersion within the laser resonator cavity. Specifically, the laser gain element has Brewster angled entrance and exit faces which allow it to operate as a wavelength dispersive element while simultaneously performing the functions of an optical gain element within a laser cavity. Wavelength tuning is effected by angular rotation of one of the end reflective elements in the cavity. By using suitable dispersive materials for the laser gain element no additional tuning elements are required providing high efficiency, low threshold laser operation for a variety of optical excitation methods. The laser gain element replaces other discrete intracavity laser tuning means required for tunable lasers, including prisms, diffraction gratings, and birefringent filter elements.

Abstract: A laser alignment apparatus is provided for generating a plurality of mutually perpendicular laser beams. The apparatus further includes rotatable beam diverters selectively hingedly moveable into or out of positions for diverting one of the laser beams. The beam diverters may be rotated about an axis coincident with the associated laser beam for sweeping laser planes. The laser planes swept by the respected beam diverters are mutually perpendicular to one another, and each laser plane is parallel to the other beams generated by the apparatus.

Abstract: A laser oscillating apparatus equipped with a folded-type laser resonator designed to fold an optical axis by using a reflecting mirror (11) in addition to an output coupling mirror (4) and a rear mirror (10). The rear mirror (10) consists of a roof reflector having a ridge (10a) set at an angle of .pi./4 with respect to a plane generated by a folded optical axis. At this time, the reflectance of the rear mirror (10) is higher in a linearly polarizing component having an electric-field vector parallel to the direction of the ridge (10a) than that in a component having an electric-field vector orthogonally intersecting the ridge. The laser beam in the resonator is linearly polarized in the direction of the ridge (10a) in an optical path running between the rear mirror (10) and the reflecting mirror (11) closest to the rear mirror (10). The linearly polarized beam is reflected by the reflecting mirror (11). The reflecting mirror (11) generates a total .pi.

Abstract: A system for combining a plurality of laser beams into a combined output beam from at least two laser sources includes the removal of conventional perpendicularly oriented output windows from each of the laser sources. Reflecting mirrors are positioned perpendicular to the optical axis at the rear of the two laser sources. A fully reflecting mirror is positioned perpendicular to the optical axis of the first laser source to reflect coherent light received from the first laser source. A beam splitter is positioned between the first laser source and the fully reflecting mirror at the intersection of the optical axes of the first and second laser source. The beam splitter directs a portion of received coherent light into a combined output beam, with the remainder being directed back to the first and second laser sources.

Abstract: A laser irradiation nozzle free from clogging, adhesion of metal oxides, directional gas blowing, and oxidation occurring on the weld; yet capable of providing sound bead morphology and a stable weld depth on a workpiece. Accordingly, the laser irradiation nozzle comprises a conical outside nozzle and a conical inside nozzle being arranged as such to give a concentric ring-shaped top, having an assist gas outlet being established between the inside and the outside nozzles, wherein, the distance h between the laser beam focal position on the workpiece and said irradiation nozzle is controlled to a predetermined value, and the ratio of the cross sectional area of the assist gas outlet being as defined between the outside and the inside nozzles to the cross sectional area of the inside concentrical ring defined by the outer diameter of said ring on the nozzle top is also controlled to a predetermined value.

Abstract: A microlaser is described which is electrostatically tunable. One of the reflectors includes at least one reflecting part whose distance from the other reflector can be adjusted to change the effective optical distance between the reflectors and thus tune the optical frequency at which lasing occurs. The disclosure brings out that the inventive aspect is also applicable to other optical devices having reflectors defining a Fabry-Perot cavity. An optical interconnecting scheme for processors using the microlaser is also described.

Abstract: An optical parametric oscillator/laser system includes an optical pump source for generating pump radiation and an embedded dual optical resonator containing an optical parametric oscillator/laser crystal. The embedded dual optical resonator includes a laser resonator and an optical parametric oscillator resonator. The OPOL crystal is an optical parametric oscillator material doped with ions that exhibit lasing transitions. The pump radiation stimulates generation of laser radiation. When the laser radiation reaches the parametric threshold, optical parametric radiation is generated. In one embodiment, the laser resonator and the OPOL resonator are each defined by spaced-apart mirrors. In another embodiment, the OPOL system includes an OPOL rod having end caps at each end. Each end cap includes surfaces for internally reflecting the laser radiation and the parametric optical radiation in a closed loop path so that the OPOL rod and the end caps define an optical resonator.

Abstract: An adjustable laser module mounting device which includes an inner socket fastened to a lens holder through a screw joint to hold a condensing lens by a rubber ring, a laser diode fastened to the inner socket at the back, an adjusting end block, and a printed circuit board connected between the laser diode and the adjusting end block. The focal distance of the condensing lens is adjusted by rotating the lens holder on the inner socket in either direction. The alignment of the laser diode with the condensing lens is adjusted by turning the adjusting end block in either direction.

Abstract: This invention relates to face-pumped slab lasers of the type that have laser head assemblies constructed of individual components, which are rigidly attached together, in order to form an integral structure. Such structures of this type, generally, allow a face-pumped slab laser component to be assembled and disassembled easily and quickly.

Abstract: An optical beam switching mechanism is used from switching a light beam between a plurality of light beam paths. A rhombic prism is mounted for rotation on an axis and is rotated between positions by a geneva mechanism. A plurality of microswitches are positioned to reposition the prism after rotation to a predetermined position. The geneva mechanism is driven by an electric motor and has an index wheel attached to a cradle supporting the prism which index wheel is rotated by a drive arm connected to the electric motor.

Abstract: A coupled multiple output ring laser system having a plurality of ring lasers 100,200 that are coupled together, each ring laser having separate output beams 159,280 and separate suppressor mirrors 228,282, is provided with two optical trombones 250,252 mounted on a common phase shifter 268, which changes the optical path length to the suppressor mirror 228 in the laser 100 and changes the optical path length of the mutual coupling path between the laser 100 and the laser 200 in an equal and opposite direction, thereby changing the phase of the output beam 159 of the laser 100 with respect to the output beam of the laser 200, without changing the phase of the output beam 280 from the laser 200. The invention works for any number of lasers and works equally well with reverse-to-forward coupling or forward-to-reverse coupling schemes.

Abstract: In a laser processing apparatus according to the present invention, an aberration compensating device is provided between a beam forming section and a half mirror. The compensating device makes a focal point of visible light used as reference light during observation and a focal point of infrared laser light used during processing coincide with each other. In one embodiment of the aberration correcting device includes an aberration correcting convex lens having long focal length and a space portion provided in a rotatable lens holder. When observing an object to be processed, the lens holder is rotated to bring the space portion into an optical path. During processing, the lens holder is rotated to bring the convex lens for correction into the optical path, e.g. when emitting the laser beam. The laser beam is converged until incidence on the objective lens by the convex correcting lens to correct the aberration.

Abstract: A helium-cadmium laser having high reflector mirror and output coupler mirror properties which favor lasing at 353.6 nm while inhibiting lasing at 325.0 nm. The preferred characteristics of the high reflector and/or output coupler mirrors include transmission at 325.0 nm greater than 10% and transmission at 353.6 nm less than 5%.

Abstract: A solid state laser provided with a solid state laser medium, a laser-medium pumping unit for performing an optical-pumping of the solid state laser medium, an optical reflection unit having a pair of a total reflection member for performing a total reflection of oscillating laser light and an output member for transmitting and outputting a part of the oscillating laser light, a reflection surface of which is coated with a reflection film having a Gaussian-type reflectivity distribution in the direction perpendicular to an optical axis of the solid state laser medium. In this solid state laser, the radius of curvature of the reflection surface of the output member, is established in such a manner that laser oscillation is efficiently performed between the total reflection member and the output member.

Abstract: A surface-emitting semiconductor injection laser for use in fabricating high-power two-dimensional monolithic laser arrays. The surface-emitting semiconductor laser includes a substrate and an active layer and a pair of cladding layers formed on the substrate. A folded resonator cavity is formed by highly-reflective 45.degree. and 90.degree. micromirrors that are etched at either end of the active layer and by a partially-reflective reflector that is positioned between the 45.degree. micromirror and the substrate for outcoupling the laser light from the resonator cavity. The semiconductor laser is mounted junction down on a heat sink to position the active layer close to the heat sink for good heat dissipation at high power levels. In one preferred embodiment of the present invention, the substrate is optically opaque and an opening is etched in the substrate for outcoupling the laser light.

Abstract: Intracavity Raman lasers comprising a pump resonator and a Raman resonator that eliminates alignment problems associated with multi-mirror intracavity lasers. The pump resonators include a laser rod and a pump source. In one embodiment, a first retroreflector is disposed at one end of the pump resonator, and an output mirror is disposed at an opposite end thereof. A Q-switch, a dichroic mirror, and a prism are disposed between the laser rod and the output mirror. The pump resonator radiates pump energy at a first wavelength (1.06 .mu.m) between the first retroreflector and the output mirror. The Raman resonator includes a Raman gas cell having first and second lenses disposed on opposite ends thereof for focusing laser energy into the Raman cell, and a second retroreflector that forms one end of the Raman resonator. The output mirror forms an opposite end of the cell, and the dichroic mirror and the prism are disposed between the second retroreflector and the first lens.

Abstract: An internally folded scalable laser has a gain medium with an internal face nd an external face and at least one internal-fold face subtending an angle which may be about 90.degree.. An output coupler that is partially reflective of the resonator mode is oriented to receive and reflect resonator mode in a direction normal to the internal face to avoid resonator mode astigmatism and to define a folded hemispherically-shaped resonator cavity extending from the output coupler and through an active volume in the gain medium to the external face. A pumping mode source disposed adjacent to the external face is oriented to focus a first pumping mode in a direction normal to the external face in a boom waist at or inside the external face in the folded resonator cavity to define an active volume in the gain medium and to avoid pumping mode astigmatism.

Abstract: A laser system provides output wavelengths at near 1.06 and near 1.44 micron from an Nd:YAG gain medium, along with a frequency doubled output of the 1.06 micron line. This system is based on a laser resonator with a plurality of turning mirrors, each transmissive at a selective subset of the characteristic wavelengths of Nd:YAG and reflective at a selected output wavelength. The mechanism is coupled with the turning mirrors for selectively positioning one of the plurality of turning mirrors in the optical path, directing the beam on an output coupler having a fixed position with respect to a string of components for delivering the output beam to a surgical site. Also, the mechanism can selectively remove the turning mirror from the optical path. In this case, the beam is supplied to a frequency doubling alternate resonator design and output at the second harmonic of the 1.06 micron line is generated.

Abstract: Apparatus for transforming a conventional beam of coherent light, having a Gaussian energy distribution and relatively high divergence, into a beam in which the energy distribution approximates a single, non-zero-order Bessel function and which therefore has much lower divergence. The apparatus comprises a zone plate having transmitting and reflecting zones defined by the pattern of light interference produced by the combination of a beam of coherent light with a Gaussian energy distribution and one having such a Bessel distribution. The interference pattern between the two beams is a concentric array of multiple annuli, and is preferably recorded as a hologram. The hologram is then used to form the transmitting and reflecting zones by photo-etching portions of a reflecting layer deposited on a plate made of a transmitting material. A Bessel beam, containing approximately 50% of the energy of the incident beam, is produced by passing a Gaussian beam through such a Bessel zone plate.

Abstract: In accordance with the present invention, an optical processing device and method are provided for processing with extremely low energy requirements. Spontaneous emissions from an excited optical gain medium generate a waveform that propagates within a cavity defined by the gain medium and a reflective device. A first spatial modulating element is disposed in the cavity in the path of the generated wavefront to impose a first spatial pattern thereon. A second spatial modulating element also is disposed in the cavity and imposes a second spatial pattern on the perturbed wavefront carrying the first pattern. When the first and second imposed spatial patterns have dual spatial pattterns, light is directed back along pathways through the cavity to induce stimulated emission and eventually resonance in the cavity.

Abstract: A laser focus compensating sensing and imaging device permits the focus of a single focal point of different frequency laser beams emanating from the same source point. In particular it allows the focusing of laser beam originating from the same laser device but having differing intensities so that a low intensity beam will not convert to a higher frequency when passing through a conversion crystal associated with the laser generating device. The laser focus compensating sensing and imaging device uses a cassegrain system to fold the lower frequency, low intensity beam back upon itself so that it will focus at the same focal point as a high intensity beam. An angular tilt compensating lens is mounted about the secondary mirror of the cassegrain system to assist in alignment. In addition cameras or CCD's are mounted with the primary mirror to sense the focused image.

Abstract: A laser output unit according to the present invention comprises a body having a laser output port at an extreme and thereof, lenses provided within said body to condense laser beam introduced to emit it from the laser output port, and a protective glass provided between said laser output port and said lens within said body. A gas jet port and a gas exhaust port opposed to said gas jet port are provided at said body portion between said protective glass and said laser output port. A gas crosses at a position between the protective glass and the laser output port. Flying matter is blown away by the gas and does not arrive at the protective glass.

Abstract: A wavelength-tunable, injection-seeded, dispersion-compensated, dispersively-pumped solid state laser includes a lasing medium; a highly reflective mirror; an output coupler; at least one isosceles Brewster prism oriented to the minimum deviation angle between the medium and the mirror for directing light of different wavelengths along different paths; means for varying the angle of the highly reflective mirror relative to the light from at least one Brewster angle for selecting a predetermined laser operating wavelength; a dispersion compensation apparatus associated with the lasing medium; a laser injection seeding port disposed between the dispersion compensation apparatus and one of the mirror and coupler and including a reflective surface at an acute non-Brewster angle to the laser beam for introducing a seed input; a dispersion compensation apparatus associated with the laser medium including opposite chirality optical elements; the lasing medium including a pump surface disposed at an acute angle to th

Abstract: A solid-state laser oscillator/amplifier system, which combines in a single laser crystal the operations of a narrow beam oscillator and a large volume amplifier, utilizes the polarization feature of the laser beam to effect coupling of an amplified beam out of the resonator in a manner which efficiently utilizes the whole volume of the active medium. The system generates a high brightness laser beam with high output energy contained in a small divergence angle.

Abstract: Lenses (30', 32') are orthogonally tilted with respect to one another in a telescope to provide imaging for an amplifier-phase conjugate mirror (PCM)(10) in a laser oscillator/amplifier (12). This mutually orthogonal tilting avoids the problem of air breakdown which occurs when the laser energy is otherwise focused at a single point and thus avoids the need to use a vacuum cell to suppress the sparking at the telescope's focus. An adjustment of the tilting of one lens (32') with respect to the other lens (30') also avoids astigmatism.

Abstract: A wedge mirror is disclosed for suppressing the high gain wavelengths in a laser. The mirror is provided with a pair of opposed surfaces lying in nonparallel planes. Each of the surfaces is provided with a wavelength selective coating. The coating on the surface of the mirror facing the gain medium is highly reflective of the high gain wavelength and highly transmissive of the low gain wavelength. This surface is oriented so that the light from the high gain wavelength is reflected out of the cavity. The outer surface of the mirror is highly transmissive of the high gain wavelength and highly reflective of the low gain wavelength. The combination of the wavelength selective coatings and the wedge configuration allows the high gain wavelength to be suppressed while the low gain wavelength oscillates. The subject mirror is particularly suited for suppressing the 1.06 and 1.33 micron wavelengths in Nd:YAG while allowing the 1.44 micron wavelength to lase.

Abstract: For small line width tuning of a laser, especially a pulsed dye laser, a reference beam is uncoupled from the laser resonator (10,18) and directed to a beam position photosensor such as an adjacent pair of photo diodes. A control signal for synchronizing the movements of a grating (10) and an etalon (18) of the laser resonator is derived from a local change of the reference beam in order that synchronism may be achieved in the movement of both the etalon and the grating.

Abstract: A ring laser (10) incorporates a laser rod (R) with end faces (R.sub.1, R.sub.2). The first face (R.sub.1) is coated for high reflectivity at the laser wavelength and the second (R.sub.2) for high transmission at this wavelength. The first face (R.sub.1) provides one cavity end mirror, and a concave mirror (M.sub.1) spaced apart from the rod (R) provides the other. A rhombic prism (P) between the rod (R) and mirror (M.sub.1) defines differing (figure of eight) forward and return paths (14 to 17, 18 to 21) for cavity radiation passing from one end mirror (R.sub.1 or M.sub.1) to the other and returning. The prism (P) presents Brewster's angle refracting surfaces. The second rod face (R.sub.2) is tilted to produce an optical path in two planes. A magnetic field (B) along the rod axis (R.sub.a) produces Faraday rotation of polarization. This counteracts rotation arising from non-coplanar optics for one direction of propagation around the laser cavity (10) but not the other.

Abstract: A semiconductor device structure capable of expanding a laser beam in one-dimension, collimating an expanding beam or focusing a nearly collimated beam. This semiconductor structure is typically comprised of three portions: a rib waveguide portion to propagate a beam of light in the quantum well region beneath the rib, an expansion region which incorporates a wider rib structure to allow the propagating beam to expand, and a rib etched lens portion to collimate the expanded beam of light. The shape of the rib etched lens portion is determined by Fermat's principle such that the optical pathlengths travelled by each ray of light are equated at a collimation plane positioned tangentially with the surface of the rib etched lens at the point at which an on-axis beam of light would strike the surface of the rib etched lens.

Abstract: A pulse laser has a laser resonator, a laser medium in the laser resonator, and a deflecting device. The laser medium emits an emission light. The deflecting device switches an optical path of the emission light to output the emission light as a laser pulse. The deflecting device includes a deflecting member and a pumping device. The deflecting member is arranged in the optical path of the emission light. The deflection member has a refractive index which changes based on a pumping light incident thereon. The pumping device radiates the pumping light on a predetermined region of the deflection member and varies the refractive index of the predetermined region to switch the optical path of the emission light.

Abstract: A laser diode which includes a substrate, a laser diode chip bonded on the substrate through a sub-mount, and a monitor element formed on the substrate or the sub-mount so as to monitor laser light emitted from a rear cleavage face of the laser diode chip. The rear cleavage face and the surface of the monitor element are connected, through a space between them, by a solid state waveguide device of a light-transmitting or semi-light transmitting nature.

Abstract: A mode locked pulsed laser incorporates an intracavity element to compensate for the dispersion caused by other intracavity elements. This element reduces the tendency of the pulse to broaden in the cavity due to group velocity dispersion and results in very short pulses. In the laser of the present invention, mode locking is initiated by detecting the beat frequency between adjacent longitudinal modes using a high speed photodiode. This signal is amplified and then the frequency is divided by two. The signal is passed through an electronically adjustable phase shifter and then to a power amplifier. This signal is applied to the acousto-optic modelocker. If the cavity length drifts the beat frequency between the longitudinal modes changes. The rf signal applied to the modulator changes in exactly the right manner to track the drift in cavity length. Thus the modelocker is automatically synched to the round trip of the laser cavity.

Abstract: A waveguide coupler comprises a curved end reflector mirror that images a waveguide exit back into the waveguide with an essentially exact reproduction of the waveguide output intensity distribution. The coupler also comprises a lens disposed near the waveguide exit at a point between the exit and the mirror, the lens providing a phase compensation to the beam passing therethrough such that the phase of the beam returned to the waveguide matches that of the exiting beam. Thus, coupling losses due to clipping of the returned beam at the exit/entrance to the waveguide bore and coupling losses due to a mismatch of the returning field phase to that of the waveguide mode are made essentially zero.

Abstract: A one-dimensional semiconductor laser array assembly typically comprising a one-dimensional semiconductor laser array, a heatsink upon which the laser array is bonded, and a lens assembly. The one-dimensional semiconductor laser array consists of a plurality of emitters with each emitter electrically connected in parallel to a power supply. The bonding agent, typically silver epoxy, must be of a uniform thickness so that the laser array is aligned properly upon the heatsink. The lens assembly is typically comprised of a refractive lens, typically of a bi-convex design, and a one-dimensional array of binary optical elements. The one-dimensional array of binary optical elements is designed such that each element has a front surface having a binary optic diffractive element etched thereon. The refractive lens and the one-dimensional array of binary optical elements are aligned and held in place by means of ears protruding from the heatsink.

Abstract: A device for modulating light, wherein a layer of material having a superconducting state is placed in the optical path of a light source and is switched between transparent, non-superconducting and non-transparent, superconducting states by a modulation circuit, thereby providing optical data modulation. A cooling device is provided to maintain the layer of material in its superconducting state. The light source is maintained at a constant optical output which reduces spectral dispersion.

Abstract: A semiconductor laser device comprises a semiconductor laser which oscillates a fundamental wave, and a transparent waveguide which is installed substantially in parallel to a direction of a cavity of the semiconductor laser and integral with the semiconductor laser, where second harmonics of the fundamental wave travel through the transparent waveguide and are emitted therefrom. The semiconductor laser and the transparent waveguide have a refractive index in a prescribed range respectively, and an output of second harmonics being significantly high in comparison to the prior art can be obtained.

Abstract: In optical isolators composed of a polarizer, an analyzer, a Faraday rotator and permanent magnet for magnetizing the Faraday rotator for the Faraday effect, this invention enables controlling of the maximum isolation temperature in the 0.degree. to 70.degree. C. temperature range. When assembling the device at room temperature, the Faraday rotator's wavelength-dependence characteristics are used for this purpose. By varying the wavelength during the assembly and adjustment process by .DELTA..lambda. from the wavelength at the device will be used, it is possible to set the temperature at which maximum isolation will be realized.

Abstract: The present invention relates to a laser oscillator, especially to a laser oscillator suitable for ultrafine manufacturing such as an apparatus for manufacturing of a semiconductor wherein the laser oscillator is provided with constant directivity chronically, although the directivity is not so fine, for avoiding a blurred image spatially and chronically in order to obtain a stable mask in the ultrafine manufacturing.

Abstract: In a system for adjusting a laser oscillator, a laser beam from a laser oscillator is detected by a power detector 22 and one of the resonant mirrors is tiltably supported by a tilting mechanism. Power signal from the detector is sampled and sampled signals are averaged by a central processing unit to obtain power average values. The power average values are compared with a power distribution curve which relates to a tilting angle of the resonant mirrors. Thus, the central processing unit determines a control value corresponding to the tilting angle of the resonant mirrors.

Abstract: An unstable laser with improved beam quality has a laser medium and a pair of crossed Porro prism end reflectors positioned to form a resonator defining a light path through the laser medium. Beam expansion optics magnify the beam with each pass through the resonator and is accomplished with a negative lens at one end of the resonator and a telescope at the other end. The negative lens produces a diverging beam through a laser medium in one direction and the telescope recollimates the beam in the reverse direction. Radially varying birefringent compensation is accomplished in the resonator with a crystalline waveplate. Output coupling is achieved through the use of the waveplate in conjunction with polarizer optics.

Abstract: In a photon storage ring for storing SR light to generate the same through an outlet port, a reflection mirror is disposed to surround a circular orbit along which bundles of charged particles revolve at a speed close to the velocity of light, generating SR light at a direction tangential to the circular orbit. The reflection mirror has curvature such that the SR light generated in the tangential direction is reflected on the reflection mirror and sent as reflection SR light which is tangential to the orbit. The SR light and the reflection SR light interfere with each other and are guided towards the outlet port.

Abstract: A linear cavity laser system having a yttrium-aluminum-garnet laser rod for producing a fundamental wavelength of radiation having a front face and a longitudinal axis, a first mirror reflective of the fundamental wavelength but transmissive of a desired harmonic wavelength located in front of the laser rod along the longitudinal axis, a second mirror reflective of both the fundamental wavelength and the desired harmonic wavelength located to a rear of the lasing rod along the longitudinal axis, a phase matched crystal harmonic wavelength generator responsive to the fundamental wavelength for generating the desired harmonic wavelength of radiation arranged between the front mirror and the lasing rod along the longitudinal axis and a dichroic member transmissive of the fundamental wavelength but reflective of the harmonic wavelength arranged between the laser rod and the harmonic wavelength generator along the longitudinal axis.

Abstract: A laser apparatus and method is disclosed comprising a first lasant material which is located in an optical cavity and which produces laser radiation of a first wavelength, and a second lasant material which is pumped by radiation from the first lasant material, which absorbs laser radiation at the first wavelength in an amount generally comparable to the Optimum Output Coupling, which functions as the output coupler for the optical cavity and which lases at a second wavelength. The first lasant material and the second lasant material are preferably selected to have minimal losses such that there is a net gain in the cavity.

Abstract: Laser apparatus is described in which the optical cavity of a laser oscillator is specially provided with a polarizing device which has on its outer face a partially reflecting coating (such as a thin partially reflecting layer of low-loss dielectric material). The polarizing device serves both as an output coupler for narrow linewidth laser emission from the optical cavity and also as a means for substantially suppressing amplified spontaneous emission (ASE). A multiple-prism Littrow-mounted grating (MPL) dye laser apparatus embodying the invention achieves a laser linewidth of less than about 0.1 GHz (.DELTA..nu.), a ratio of intensity I of the ASE to the intensity I.sub..lambda. of the desired laser emission of about 10.sup.-10, an efficiency of somewhat more than 10%, and a short optical cavity length of less than 10 cm. The apparatus is also more rugged, more stable in frequency with changes in temperature, and less costly than similar previous lasers.

Abstract: A laser (15) is mounted on a planar surface of a monocrystalline silicon mounting member (12). A spherical lens (20) is mounted in a monocrystalline silicon cover member (13) which, when abutted and registered to the mounting member (12), aligns the spherical lens with the laser so that the output light can be projected along a precise predetermined path. The spherical lens (20) is mounted in a first V-shaped groove (31) which is made in the cover member by masking and etching. A second V-shaped groove intersects the first groove and defines a V-shaped edge in one side of the first groove. The spherical lens is then seated in the first V-shaped groove such that it bears against two points of the V-shaped edge and against one side wall (35) of the first V-shaped groove. A second lens (19) is mounted in the cover member in the same manner as the first lens and directs laser light from a rear facet of the laser to a mirror 30 and hence to a photodetector (21) mounted in the cover member.

Abstract: A semiconductor laser device includes a semiconductor laser element having a quantum well structure active layer having n levels of quantum states (n.gtoreq.2) from the first quantum level to the n-th quantum level in which the front facet reflectivity and the rear facet reflectivity are asymmetrical so that oscillation can occur at the n-th quantum level, a reflecting mirror having a reflectivity that causes oscillation of the semiconductor element to occur at a quantum level lower than the n-th quantum level, and a reflecting mirror moving unit for positioning the reflecting mirror in the neighborhood of the front facet or the rear facet of the semiconductor laser element. Therefore, a semiconductor laser device which can oscillate at two or more wavelengths with a simple construction is obtained.

Abstract: An improved dye laser having a birefringent tuning filter comprised of one or more birefringent plates wherein each plate is oriented at Brewster's angle to the resonant light beam and is an integer multiple of the thickness of the thickness of the first plate characterized by the fact that the thickness of the first plate is chosen using a new tuning relationship so that a single order tuning curve covers a tuning range of interest. This single tuning curve is almost linear throughout the tuning range and has a tuning angle at the center of the range of approximately five degrees. Also, the tuning curve has a slope throughout the tuning range which provides sensitivity of selected wavelength to tuning angle which is neither too great nor too small. A further refinement in the structure is a non-birefringent polarizing plate at Brewster's angle which increases the losses imposed upon light passing therethrough which is polarized at other than Brewster's angle.