Abstract: Provided is a long wavelength laser of which the operating point is stabilized and the laser oscillation is stabilized. The long wavelength laser comprises a resistor element provided to a portion where the surface current is maximum in a surface plasmon waveguide to stabilize a potential difference between a first cladding and a second cladding in the surface plasmon waveguide.

Abstract: A system generates FIR radiation. An electron source generates an electron beam. A first horn interacts with the electron beam to produce the FIR radiation. A second grating horn receives the electron beam from the first horn and emits it as a collimated free wave or Smith-Purcell radiation.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.

Abstract: The present invention relates generally to a terahertz and millimeter wave source, and more particularly, but not exclusively, to structures for coupling the terahertz electromagnetic waves out of the source.

Abstract: Apparatus and methods for generating radiation via difference frequency generation (DFG). In one exemplary implementation, a quantum cascade laser (QCL) has a significant second-order nonlinear susceptibility (?(2)) integrated in an active region of the QCL. The QCL is configured to generate first radiation at a first frequency ?1, second radiation at a second frequency ?2, and third radiation at a third frequency ?3=?1??2 based on difference frequency generation (DFG) arising from the non-linear susceptibility. In one aspect, the QCL may be configured to generate appreciable THz radiation at room temperature.

Abstract: An object is to provide a method capable of boring a borehole even when quartz glass or silicon dioxide is deposited as molten dross by laser irradiation. A laser irradiation position of a workpiece is irradiated with a laser having wavelength of 1.2 ?m or longer and a high factor of absorption into liquid, for example, a CO2 laser, from a laser oscillator through liquid. By high pressure generated in an advancing microbubble flow occurring in the liquid, molten dross is scattered. Thus, the processing, such as boring, of the rock is performed.

Abstract: A laser system capable of efficient production of high energy sub-nanosecond pulses in the 2-15 ?m spectral region is disclosed. Diode pumped solid state lasers are used as pump sources. The system design is simple, reliable and compact allowing for easy integration. The laser system includes a combination of compact solid-state ˜1 micron laser sources, producing high power picosecond pulses, with optical parametric amplification and a quasi-continuous wave laser for seeding the amplification process that enables the efficient conversion of the high power ˜1 micron laser radiation to tuneable mid-infrared sub-ns pulses. New parametric processes are presented for achieving high gains in bulk nonlinear crystals. Furthermore, a method of exceeding the fundamental conversion efficiency limit of direct three wave mixing is presented.

Abstract: A compact high average power mid infrared range laser for ultrasound inspection. The laser comprises one of a Nd:YAG or Yb:YAG laser pumped by a diode at 808 nm to produce a 1 micron output beam. The 1 micron output beam is directed to an optical parametric oscillator where the beam wavelength is converted to 1.94 microns and conveyed to a mid infrared emission head. The emission head comprises one of a Ho:YAG or Ho:YLG laser optically coupled with a second optical parametric oscillator. The second optical parametric oscillator forms a generation output beam for creating ultrasonic displacements on a target. The generation output beam wavelength ranges from about 3 to about 4 microns, and can be 3.2 microns.

Abstract: A photo-semiconductor device comprises a photoconductive semiconductor film provided with electrodes and formed on a second substrate, the semiconductor film being formed by epitaxial growth on a first semiconductor substrate different from the second substrate, the second substrate being also provided with electrodes, the electrodes of the second substrate and the electrodes of the photoconductive semiconductor film being held in contact with each other.

Abstract: The invention is in the field of laser radiation generation in bands II and III, and relates to a device for generating laser radiation in the infrared having means for modifying the amplified-radiation frequency and using the Raman effect, characterized by additionally having at least one diode able to emit laser radiation in the 1.8-2.1 ?m frequency range, at least one current generator able to generate current levels at an adjustable repetition rate, means for supplying said current levels to said diode, and means for amplifying the laser radiation emitted by said diode and comprised of at least one fiber doped with an ion having laser activity in the diode emission range.

Abstract: The present invention provides quantum cascade lasers and amplifier that operate in a frequency range of about 1 Terahertz to about 10 Terahertz. In one aspect, a quantum cascade laser of the invention includes a semiconductor heterostructure that provides a plurality of lasing modules connected in series. Each lasing module includes a plurality of quantum well structure that collectively generate at least an upper lasing state, a lower lasing state, and a relaxation state such that the upper and the lower lasing states are separated by an energy corresponding to an optical frequency in a range of about 1 to about 10 Terahertz. The lower lasing state is selectively depopulated via resonant LO-phonon scattering of electrons into the relaxation state.

Abstract: Provided is a frequency-tunable terahertz light source device. The frequency-tunable terahertz light source device satisfies a Littrow diffraction condition at a wavelength and simultaneously satisfies a Littman-Metcalf diffraction condition at another wavelength using a double diffraction grating having two grating periods. Thus, oscillations simultaneously occur at the two different wavelengths, such that a terahertz wave can be stably generated by beating of the two oscillation wavelengths. In addition, the frequency-tunable terahertz light source device can readily change a frequency up to several terahertz and can be fabricated in a small size.

Abstract: Disclosed are a laser module apparatus and a display apparatus using the same. In accordance with an embodiment of the present invention, a laser module package which generates a green laser beam can include a pumping light source, configured to generate and output a pump beam; a laser medium, configured to receive the pump beam and output an infrared beam; an optical crystal, configured to receive the infrared beam and output a laser beam having a green wavelength band; and a micro heater, configured to be thermally coupled to the pumping light source and control an operation temperature of the pumping light source to be maintained to a predetermined target temperature.

Abstract: A compact mid-IR laser device utilizes a quantum cascade laser to provide mid-IR frequencies suitable for use in molecular detection by signature absorption spectra. The compact nature of the device is obtained owing to an efficient heat transfer structure, the use of a small diameter aspheric lens and a monolithic assembly structure to hold the optical elements in a fixed position relative to one another. The compact housing size may be approximately 20 cm×20 cm×20 cm or less. Efficient heat transfer is achieved using a thermoelectric cooler TEC combined with a high thermal conductivity heat spreader onto which the quantum cascade laser is thermally coupled.

Abstract: A laser beam projector employs a light engine including a semiconductor laser platform (20) emitting a plurality of infrared laser beams and a frequency converter (30) emitting a plurality of primary color laser beams as a frequency conversion of the plurality of infrared laser beams, wherein each primary color laser beam has a primary color wavelength corresponding to a high sensitivity of a human eye. The laser beam projector further employs a laser beam mixer (40) emitting a projection laser beam as a mixture of the plurality of primary color laser beams.

Abstract: In a method for generating a terahertz electromagnetic wave by using coherent phonons in a quantum structure, high density of coherent phonons acting as a radiation source of the terahertz electromagnetic wave are obtained by exciting the inter-band transitions in a quantum structure under the condition that the energy difference between two inter-band transitions in the quantum structure is resonated with the energy of the coherent phonons, and the terahertz electromagnetic wave is generated by the oscillatory polarizations of the coherent phonons. High density of coherent phonons may be created through the elementary excitation generated by using instantaneous laser pulses. A quantum well structure is effective as the quantum structure, and a scattering process of coherent phonon may be suppressed by confining coherent LO phonons in a well layer.

Abstract: An optical continuum source is formed that is used to generate both a continuum and one or more light peaks outside the bandwidth of the continuum. In particular, one or more fiber Bragg gratings exhibiting a resonant wavelength less than the short wavelength edge (or greater than the long wavelength edge) of a predetermined continuum are inscribed into a section of highly nonlinear fiber (HNLF) and used to generate the additional light peaks. Gratings may also be formed for areas along the fiber where the continuum spectral power density is essentially “zero”. It has been discovered that the use of a Bragg grating generates phase matching with the propagating optical signal, thus resulting in the creation of the additional peaks.

Abstract: Provided is a vertical cavity surface emitting device. The surface emitting device includes a lower mirror layer emitting light having a long wavelength, an active layer providing an optical gain, a tunnel junction layer for confining a current, and an upper mirror layer, which are sequentially stacked on a compound semiconductor substrate, wherein a heat release layer is formed on side surfaces of at least one of the active layer, the tunnel junction layer and the upper mirror layer by using etching process, and the heat release layer has greater thermal conductivity than at least one of the active layer, the tunnel junction layer and the upper mirror layer.

Abstract: An electrically-pumped terahertz (THz) frequency radiation source (or detector), including an optical gain (or absorption) material with two electrodes electrically coupled to the optical gain material. The optical gain (or absorption) material is formed substantially of at least one group IV element and doped with at least one dopant, which has an intra-center transition frequency in a range of about 0.3 THz to 30 THz. Also, a method of manufacturing electrically-pumped THz frequency radiation sources (or detectors).

Abstract: A semiconductor laser comprises an active region (12) which, in response to a pumping energy applied thereto, can produce a stimulated emission of radiation with a central wavelength (?) in the far infrared region, and a confinement region (16, 18, 22) suitable for confining the radiation in the active region (12), and comprising at least one interface (16a, 16b, 22a) between adjacent layers that is capable of supporting surface plasmon modes generated by an interaction of the interface with the radiation. The confinement region (16, 18, 22) comprises a wave-guide layer (16) which is delimited on opposite sides by a first interface and by a second interface (16a, 16b).

Abstract: An apparatus for producing wavelength stabilized electromagnetic radiation is provided, the apparatus comprising a broadband semiconductor radiation source configured to produce broadband electromagnetic radiation having a mean wavelength ?m, and a bandpass radiation filter, an input of said bandpass radiation filter being in optical connection to an output of said radiation source, and a common temperature stabilizer being in thermal contact with both, the radiation source and the radiation filter. In a preferred embodiment, the radiation source—which is, for example, a superluminescent light emitting diode—and the bandpass radiation filter are provided on a common mount which is in contact with a thermoelectric cooler acting, together with temperature sensing means and control means, as temperature stabilizer.

Abstract: A method of tuning optical components integrated on a monolithic semiconductor chip having a plurality of first optical components integrated on the chip with each fabricated to approximate an emission wavelength along a given wavelength grid and together forming a first optical component wavelength grid. A second optical component is integrated on the chip with and optically coupled to the group of first optical components. The second optical component has a second optical component wavelength grid approximating the given wavelength grid where at least one emission peak along the second optical component wavelength grid is within an acceptable wavelength tolerance range of a particular first optical component of the first optical component wavelength grid but not the same as a corresponding emission wavelength of a particular first optical component.

Abstract: An infrared laser has a seed laser with an optical seed output. A pump amplifier receives the optical seed output and has an amplified output. A molecular gas laser receives the amplified output and has an infrared optical output.

Abstract: A method for converting a Type 2 quantum well semiconductor material to a Type 1 material. A second layer of undoped material is placed between first and third layers of selectively doped material, which are separated from the second layer by undoped layers having small widths. Doping profiles are chosen so that a first electrical potential increment across a first layer-second layer interface is equal to a first selected value and/or a second electrical potential increment across a second layer-third layer interface is equal to a second selected value. The semiconductor structure thus produced is useful as a laser material and as an incident light detector material in various wavelength regions, such as a mid-infrared region.

Abstract: Electromagnetic radiation sources operating in the Terahertz (THz) region capable of overcoming the Manley-Rowe limits of known optical schemes by achieving phase matching between a THz wave and optical pulse in a nonlinear waveguide, or by achieving both phase and group velocity matching between a THz wave and optical pulse in a nonlinear waveguide to yield even higher efficiencies in converting optical power to the THz region.

Abstract: A narrow line width optical parametric oscillator (OPO) (10) is used a pump for a tunable optical parametric oscillator to enable it to produce a mid and long wavelength IR output over a wide 5–20 micron bandwidth. The pumping OPO (10) is then set up to be non-colinearly phase matched. To enable the pumping OPO (10) to exhibit the narrow line width, it is seeded with a narrow line width seeding source. The result is output energy having an extremely narrow 4 nanometer line width. The narrowness of the pumping OPO (10) output is derived first by using non-colinear phase matching in the pumping OPO (10) and secondly by using seeding in the pumping of the pumping OPO (10).

Abstract: A fiber laser including doped-core fiber having inner and outer cladding is optically pumped by plurality of diode-lasers. Light emitted by the diode-lasers is coupled into a single multimode optical fiber. Light from the multimode optical fiber is directed to a wavelength selective reflecting device that is partially reflective in a narrow reflection band about a peak reflection wavelength. A portion of the light having the peak reflection wavelength is reflected from the wavelength selective reflecting device back along the multimode optical fiber and back into the plurality of diode-lasers. This locks the emitting wavelength of the light emitted from each of the diode-lasers to the peak reflection wavelength. Light at the emitting wavelength that is not reflected from the wavelength selective reflective device is coupled into the inner cladding of the doped-core fiber for optically pumping the fiber laser.

Abstract: The present invention provides quantum cascade lasers and amplifier that operate in a frequency range of about 1 Terahertz to about 10 Terahertz. In one aspect, a quantum cascade laser of the invention includes a semiconductor heterostructure that provides a plurality of lasing modules connected in series. Each lasing module includes a plurality of quantum well structure that collectively generate at least an upper lasing state, a lower lasing state, and a relaxation state such that the upper and the lower lasing states are separated by an energy corresponding to an optical frequency in a range of about 1 to about 10 Terahertz. The lower lasing state is selectively depopulated via resonant LO-phonon scattering of electrons into the relaxation state.

Abstract: There is provided a semiconductor laser device implementing a single transverse mode oscillation in an oscillation wavelength of 780 nm band and also having high reliability and long life in high-output driving state, and an optical disk recording and reproducing apparatus with use of the semiconductor laser device. A multiple quantum well active layer 105 is composed of InGaAsP, and a first cladding layer 103, a second cladding layer 107, a third cladding layer 109, and a first current blocking layer 112 are structured from III–V group compound semiconductor containing only As as V group element. Inside the first current blocking layer 112, a hollow portion 130 is provided in the vicinity of and approximately parallel to the ridge stripe-shaped third cladding layer 109.

Abstract: A method and apparatus for producing a very high repetition rate gas discharge laser system in a MOPA configuration is disclosed which may comprise a master oscillator gas discharge layer system producing a beam of oscillator laser output light pulses at a very high pulse repetition rate; at least two power amplification gas discharge laser systems receiving laser output light pulses from the master oscillator gas discharge laser system and each of the at least two power amplification gas discharge laser systems amplifying some of the received laser output light pulses at a pulse repetition that is a fraction of the very high pulse repetition rate equal to one over the number of the at least two power amplification gas discharge laser systems to form an amplified output laser light pulse beam at the very high pulse repetition rate, which may be positioned in series with respect to the oscillator laser output light pulse beam.

Abstract: Selectively oxidized vertical cavity lasers emitting at about 1290 nm using InGaAsN quantum wells that operate continuous wave below, at and above room temperature are reported. The lasers employ a semi-insulating GaAs substrate for reduced capacitance, high quality, low resistivity AlGaAs DBR mirror structures, and a strained active region based on InGaAsN. In addition, the design of the VCSEL reduces free carrier absorption of 1.3 ?m light in the p-type materials by placing relatively higher p-type dopant concentrations near standing wave nulls.

Abstract: A light wavelength converting module is provided in which generation of noise due to return light is prevented and a wave whose wavelength is converted can be obtained stably. The light wavelength converting module is formed by a semiconductor laser from which a fundamental wave exits, and a light wavelength converting element which is optically coupled to the semiconductor laser and which converts a wavelength of the fundamental wave which enters from the semiconductor laser. A wavelength plate is disposed at a light exiting side of the light wavelength converting element. An IR cutting filter, which serves as a removing means for removing the fundamental wave from a second harmonic, is disposed between the wavelength plate and the light wavelength converting element.

Abstract: The present invention includes infrared emitting materials and infrared emitting devices. The present invention demonstrates 1.54 micron infrared PL and EL emission from an organic complex. This provides a very simple way to obtain a light source at 1.54 micron wavelength that may be both optically and electrically pumped.

Abstract: An electro-optic device for use with a laser beam. A crystal has a first face and a second face. Means are provided for applying a voltage across the crystal to obtain a net phase retardation on the polarization of the laser beam when the laser beam is passed through the crystal. In one embodiment the crystal is composed of a compound having the chemical formula ReAe40(BO3)3 where: RE consists of one or more of the following elements La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and two other elements Y and Sc; and where Ae is from the list of Ca, Sr, or Ba.

Abstract: Infrared generation is disclosed. A first laser field having a first frequency associated with a first interband transition is generated. A second laser field having a second frequency associated with a second interband transition is generated. The generation of the first laser field occurs substantially simultaneously with the generation of the second laser field. A third laser field is generated from the first laser field and the second laser field. The third laser field has a third frequency associated with an intersubband transition. The third frequency is substantially equivalent to a difference between the second frequency and the first frequency.

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

Abstract: An interband cascade (IC) light emitting device having narrow ridges, and a method of growing and fabricating the IC light emitting device is disclosed. The IC light emitting device produced by the method of the present invention has 18 active regions separated by n-type injection regions and a plurality of coupled quantum wells of Al(In)Sb, InAs, and Ga(In)Sb layers. The IC light emitting device produced according to the present method has a differential external quantum efficiency of at least 500%, a peak power output of at least 4W/facet, a power conversion efficiency of at least 14% in continuous wave at 80K, a power conversion efficiency of at least 18% in pulsed wave operation at 80K, a continuous wave operation temperature of 142 K or less, a thermal resistance of from about 24-29 K*cm2/kW and continuous wave output powers of at least 100 mW/facet at temperatures above 77K.

Abstract: A light wavelength converting module is provided in which generation of noise due to return light is prevented and a wave whose wavelength is converted can be obtained stably. The light wavelength converting module is formed by a semiconductor laser from which a fundamental wave exits, and a light wavelength converting element which is optically coupled to the semiconductor laser and which converts a wavelength of the fundamental wave which enters from the semiconductor laser. A wavelength plate is disposed at a light exiting side of the light wavelength converting element. An IR cutting filter, which serves as a removing means for removing the fundamental wave from a second harmonic, is disposed between the wavelength plate and the light wavelength converting element.

Abstract: Infrared generation is disclosed. A first laser field having a first frequency associated with a first interband transition is generated. A second laser field having a second frequency associated with a second interband transition is generated. The generation of the first laser field occurs substantially simultaneously with the generation of the second laser field. A third laser field is generated from the first laser field and the second laser field. The third laser field has a third frequency associated with an intersubband transition. The third frequency is substantially equivalent to a difference between the second frequency and the first frequency.

Abstract: An integrated, single output port, tunable multiple wavelength laser apparatus produces one of Na Nb wavelengths using only Na plus Nb selection signals. Each of Nb ports can output Na of the laser wavelengths, the port being selected by the Nb control signals and the particular one of the Na wavelengths being selected by the Na control signal. An Nb×1 router combines the signals from the Nb output ports into a single output.

Abstract: A method and apparatus for obtaining multiple wavelengths of varying temporal format from a single solid state laser are provided. Accordingly, the output from the solid state laser can either be sent through a series of non-linear crystals to obtain UV radiation or through an OPO cavity to obtain IR radiation. In order to provide the different wavelengths in the temporal formats commonly used for various medical procedures, the laser source may be operated in two different modes. When the laser system produces UV radiation a pulse of short duration is desired and the laser source is operated in the standard Q-switched mode or is mode locked. Conversely, when the laser system produces IR radiation, a pulse of long duration is desired and the laser source is operated in the free running mode.

Abstract: A coherent optical source, having a center frequency in the terahertz band can be generated. Two coherent optical sources of different frequencies can be mixed in a nonlinear crystal to generate an optical source having a third distinct frequency in the terahertz frequency range. The third frequency, an idler frequency, equals the difference between pump and signal wave frequencies incident on the crystal. The pump and signal wave frequencies are selected so that their frequency difference is in the terahertz range and so that the interaction between the pump, signal, and idler wave frequencies is phase matched using a cross-Reststrahlen band dispersion-compensated phasematching technique.

Abstract: Disclosed is an apparatus for generating laser pulses, which has a Q-switched solid state laser and at least one nonlinear crystal, and the application of this apparatus for removing material in the biomedical field. The present invention is distinguished by the nonlinear crystal being disposed inside the resonator of the solid state laser and by a pulse prolongation unit determining the pulse form and duration of the light pulse developing in the resonator.

Abstract: A p-Ge laser operating at submillimeter wavelengths in Voigt configuration using a regular permanent magnet. The invention is improvement over prior art Ge Lasers which use superconducting magnets that require liquid helium to cool the magnets along with the Ge crystal. Although the subject invention requires cooling(refrigerant) of the Ge crystal itself, it does not need liquid helium. The permanent magnet can be Nd.sub.2 Fe.sub.14 B. The emissions using the novel invention were observed over a wider range of electric-field magnitude in Voigt configuration at a given magnetic field as compared to that of the prior system. The free space beam profile of the subject invention is Gaussian. The emission-strength of the subject invention is sufficient between 4 and 10K that a closed-cycle refrigerator can be used to cool the crystal rather than the liquid helium used in all prior p-Ge lasers.

Abstract: A high-efficiency fluorescent emitter includes an excitation source and a w phonon host doped with erbium. The emitter can be used as a lasing medium or as a phosphor. Typical hosts include RcX.sub.3 and chalcogenide glasses, wherein Rc is yttrium, gadolinium, lutetium, lanthanum or a mixture thereof, and X is a halogen or a mixture of halogens.

Abstract: Apparatus performs a method of generating one output laser pulses in a range of 2 to 5 microns using an intracavity feature. When a plurality of the output laser pulses are generated, a first output pulse may have any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and may have a chosen wavelength differing from the selected wavelength. A pump laser cavity is provided with a tunable rod and an intracavity Raman device (in the pump cavity) to shift the wavelength of initial pump laser pulses. The intracavity Raman device generates radiation at first and second Stokes wavelengths, and the pulses at each wavelength are separated and are in separate paths for permitting separate operation thereon. The Raman device in the pump cavity increases the pump intensity inside the Raman cell and gives a much longer effective interaction length between the pump laser beam and the Raman medium.

Abstract: A continuous-wave ultraviolet laser light generating apparatus includes a laser light source unit (1) for generating laser light from visible light to near-infrared light, a wavelength converting means (4) which includes an optical resonator (2) and a wavelength convertor (3) disposed in the optical resonator (2) for converting a wavelength of incident laser light and which converts the laser light from the laser light source unit (1) into continuous-wave ultraviolet laser light L.sub.UL to emit the latter, a locking means (5) for adjusting the optical resonator (2) so as to have a predetermined cavity length, and an electrooptic phase modulator (6) for modulating a phase of the laser light from the laser light source unit in response to a resonance frequency of the optical resonator. The electrooptic phase modulator (6) is made of an electrooptic crystal (11) having a composition of ATiOXO.sub.4 where A depicts any one of K, Cs and Rb and X depicts any one of P and As.

Abstract: A miniaturized, frequency-doubled blue laser utilizing a pump source operating within a radiation band of 780 to 820 nm, such as a Ti:sapphire laser or other suitable optical pump, to pump a gain medium comprising a crystal of neodymium-doped yttrium orthoaluminate (Nd:YAlO.sub.3) and produce a fundamental radiation having a wavelength of approximately 930 nm, the fundamental radiation being subsequently frequency doubled by means of a nonlinear crystal, such as potassium niobate (KNbO.sub.3), to yield output radiation at a wavelength of 465 nm.

Abstract: Apparatus performs a method of generating one or more output laser pulses in a range of 2 to 6 microns. When a plurality of the output laser pulses are generated, a first output pulse has any selected wavelength within the range and a second output pulse is temporally closely spaced relative to the first output pulse and has a chosen wavelength differing from the selected wavelength. An oscillator laser cavity is provided with a tunable oscillator rod capable of generating initial laser pulses within a range of from 750 to 1000 nm, and a tuning element is coupled to the rod. A flashlamp is operable to pump the rod. For two pulse operation, the flashlamp has a given duration. A Q-switch provides the initial laser pulses upon operation of the tuning element and the flashlamp. A Raman device coupled to the rod shifts the wavelength of such initial laser pulse into the range of from 2 to 6 microns to form the output laser pulse having a wavelength within the range.

Abstract: An optical gain medium comprises a multi-phase system wherein: a first phase is an electromagnetic radiation emitting and amplifying phase (16) that is comprised of doped semiconductor nanocrystals; a second phase is an electromagnetic radiation scattering phase (14); and a third phase is a substantially transparent (at the wavelengths of interest) matrix phase (12). The emission phase may consist of ZnS nanoparticles that are doped with Mn.sup.2+, the scattering phase may comprise TiO.sub.2 or Al.sub.2 O.sub.3 nanoparticles, and the matrix phase may comprise a glass or polymer body, layer or coating. At least one dimension of a body, layer, or coating comprised of the gain medium may be less than a scattering length associated with the scattering phase.