Abstract: A harmonic generation microscopy employs a laser device that emits a laser beam having a predetermined wavelength that causes no autofluorescence in a biological sample and that, after excited, induces both the second and third harmonic waves. The laser beam is projected onto a sample and an observation beam from the sample is received. The observation beam is directed through a splitter to separate the second harmonic wave and the third harmonic wave both of which are then converted into corresponding electrical signals. The electrical signals are fed to a computer-based image processing equipment to form an image of the sample on the basis of the second and third harmonic waves.

Abstract: An optical circuit is designed with demultiplexing and optical detection functionality with minimal crosstalk. An Nth order harmonic generation device is positioned before the demultiplexer to either convert the frequency or down convert the wavelength of the demultiplexed light wave by N-times. Upconverting the multiplexed signal at the receiver station is performed by either simultaneously upconverting N-times to create N times the original spacing between each optical channel or by upconverting the frequency of one optical channel at a time.

Abstract: An EUV radiation source that creates a stable solid filament target. The source includes a nozzle assembly having a condenser chamber for cryogenically cooling a gaseous target material into a liquid state. The liquid target material is filtered by a filter and sent to a holding chamber under pressure. The holding chamber allows entrained gas bubbles in the target material to be condensed into liquid prior to the filament target being emitted from the nozzle assembly. The target material is forced through a nozzle outlet tube to be emitted from the nozzle assembly as a liquid target stream. A thermal shield is provided around the outlet tube to maintain the liquid target material in the cryogenic state. The liquid target stream freezes and is vaporized by a laser beam from a laser source to generate the EUV radiation.

Abstract: A system using several wavelengths, preferably from the output of a single laser, is described for curing a dual cure glue seal that affixes two substrates to form a liquid crystal display panel. Here the liquid crystal is already in place before the glue seal is cured so that a high temperature bake to promote the sealant curing is not permissible . The multiple wavelengths from the single source of radiation result both from frequency doubling and mixing of the fundamental laser to achieve frequency tripling. Generally a UV wavelength is required for curing the photolytic component of the glue seal so that in the present invention the fundamental from a ˜1 micron (1000 nm) wavelength laser is frequency tripled. The UV is scanned along the entire peripheral region of the glue seal.

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator, with non-linear behavior. The modulator receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal as tributary signal frequency.

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator, with non-linear behavior. The modulator receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal as tributary signal frequency.

Abstract: A method and apparatus for modulating light, wherein a light source provides light of a certain wavelength to be modulated by a layer of superconducting material which forms part of a specifically configured plate assembly. The superconducting layer is placed in the optical path of the light source. Further the superconducting layer is switched between a partially transparent non-superconducting state and a substantially non-transparent superconducting state by a modulation circuit. The resulting optical pulses transmitted through the superconducting layer are converted from the original wavelength to a lower wavelength by a frequency converting device.

Abstract: The circuit includes an electro-optical mixer, such as an electro-optical Mach-Zehnder modulator (2), with non-linear behaviour. The modulator (2) receives as input an optical signal (Pin) at the frequency to be divided, in addition to an electric signal (e3) at a given frequency, usually corresponding to the frequency deriving from such division. The output optical signal (Pout) from modulator (2) exhibits a modulation spectrum containing the frequency difference between the frequency to be divided and at least one harmonic of the frequency of the above electric signal. After having been converted into an electric signal (e1), the output signal of the mixer is subjected to a filtering action (8) to extract the above frequency difference component. This latter one is then used both as electrical signal (e3) for the mixing, and as output signal from the divider (e2). The preferred application is to OTDM systems, to extract a synchronism signal at tributary signal frequency.

Abstract: A light modulation system, wherein a light source provides light of a certain wavelength to be modulated by a material layer, which forms part of a specifically configured plate assembly. The modulation layer is placed in the optical path of the light source. Further, the modulation layer is switched between first and second states, and cooperates with the light source to produce a train of pulses at a given pulse rate. The resulting optical pulses transmitted through the modulation layer are converted from the original certain wavelength to a lower wavelength by a frequency converting device.

Abstract: According to the invention, a method and an apparatus for producing a laser beam having a preselected output frequency which has a longer wavelength than does the fundamental beam of the lasing medium is provided. In one aspect of the invention a laser resonator cavity is formed between two reflective surfaces such as mirrors. A lasing medium is located within the laser resonator cavity for generating a fundamental wavelength beam. An optical parametric oscillator cavity is also formed between one of the laser resonator cavity reflective surfaces and a third reflective surface for example a mirror. A nonlinear crystal cut for phase matching conditions for the fundamental beam wavelength and the output beam wavelength is located in optical communication with the first and the third reflective surfaces. The optical axis of the laser resonator and the optical parametric oscillator are at least partially separate and partially overlap.

Abstract: An organic nonlinear optical material comprising a compound having the iodonium salt structure represented by the general formula (I): ##STR1## wherein .pi..sub.1 to .pi..sub.n are the same or different and each is an atomic group having .pi. electron, I.sub.1 to I.sub.n-1 are an iodonium cation, A.sub.1 to A.sub.n-1 are the same or different and each is a counter anion for the iodonium cation, R.sup.1 and R.sup.2 are the same or different and each is a hydrogen atom or an electron donative group, and n is an integer of 2 to 4. The material has large nonlinear optical constants and shows no light absorption in the visible light region.

Abstract: One manner of construction of robust, thin film materials with large second-order optical nonlinearities is the covalent self-assembly of aligned arrays of high-.beta. molecular chromophores into multilayer superlattices. the dispersion of the large second harmonic generation (SHG) response in a self-assembled (SA) film containing stilbazolium chromophore building blocks is disclosed, as well as the fabrication of SHG waveguides with such materials.

Abstract: The design and synthesis of a family of calix[4]arene-based nonlinear optical (NLO) chromophores are discussed. The calixarene chromophores are macrocyclic compounds consisting of four simple D-.pi.-A units bridged by methylene groups. These molecules were synthesized such that four D-.pi.-A units of the calix[4]arene were aligned along the same direction with the calixarene in a cone conformation. These nonlinear optical super-chromophores were subsequently fabricated into covalently bound self-assembled monolayers on the surfaces of fused silica and silicon. Spectroscopic second harmonic generation (SHG) measurements were carried out to determine the absolute value of the dominant element of the second-order nonlinear susceptibility, d.sub.33, and the average molecular alignment, .PSI.. A value of d.sub.33 =60 pm/V at a fundamental wavelength of 890 nm, and .PSI..about.36.degree. was found with respect to the surface normal.

Abstract: A third-order nonlinear optical material having a metal oxide contained in a transparent polymer.

Abstract: A third-order nonlinear optical material comprising a complex compound represented by the general formula:A.sub.k B.sub.l (LIG.sub.a).sub.i (LIG.sub.b).sub.j (1)wherein A represents one metallic element selected from the group consisting of Cr, Mo and W; B represents one metal selected from the group consisting of Ni, Pd and Pt; each of LIG.sub.a and LIG.sub.b represents one ligand selected from the group consisting of monodentate and higher ligands; k is an integer of 0 or 1 to 4; l is an integer of 0 or 1 to 4; k+l is 2 or 4; i is an integer of 0 to 18; j is an integer of 0 to 18; and i+j is an integer of 1 to 18; provided that i and i+j are determined depending on the type and number of metals and the types of LIG.sub.a and LIG.sub.b.

Abstract: A method and apparatus for modulating light, wherein a light source provides light of a certain wavelength to be modulated. A light modulating device is placed in the optical path of the light source. The resulting optical pulses transmitted through the light modulating device are converted from the original wavelength to a lower wavelength by a frequency converting device.

Abstract: A multiple-stage optical Kerr gate system for gating a probe pulse of light. In a first embodiment, the system includes at least two optical Kerr gates, each Kerr gate including a polarizer, an optical Kerr cell actuable by a pump pulse, and an analyzer. In a second embodiment, at least one of the Kerr cells may be eliminated by arranging the respective sets of polarizers and analyzers so that they share a common Kerr cell. Gated pulses obtained using the present system typically have a signal to noise ratio that is at least 500 times better than that for gated pulses obtained using a single optical Kerr gate system. The system of the present invention may also include means for causing the pump pulse to arrive at the second Kerr cell (in the case of the first embodiment) or at a single Kerr cell a second time (in the case of the second embodiment) non-synchronously with the arrival of the probe pulse thereat.

Abstract: The present invention provides a nonlinear optical element having a sufficient thickness that can be used as a thin film insusceptible to crack and a process for the preparation thereof. A novel nonlinear optical element which gives a nonlinear response to incident light is provided, comprising finely divided grains of a semiconductor or metal, which grains have been separated out with the reaction of a functional group in a matrix-forming substance containing said functional group, dispersed in a matrix. A process for the preparation of a nonlinear optical element which gives a nonlinear response to incident light is also provided, which comprises mixing a solution of a matrix-forming substance containing a functional group with a metal, a semiconductor or a precursor thereof to form a uniform solution, and then allowing said functional group to undergo reaction to form a matrix while allowing finely divided grains of said metal or semiconductor to be separated out in said matrix.

Abstract: An optical system uses a nonlinear optical medium to alter the frequency of a relatively narrow band light source tunable over a plurality of different frequencies using an optical system for passively directing light to the nonlinear medium at a correct phase matching angle. In this manner, the light from the tunable light source can be efficiently frequency-doubled or frequency-tripled without the need of moving parts. An all prism design provides a system of optimal efficiency.

Abstract: There are provided a third-order nonlinear optical material comprising a film formed on the surface of a transparent substrate and consisting essentially of an oxide of a metal selected from the group consisting of V, Cr, Mn, Fe, Co, Ni and Cu; and a third-order nonlinear optical material of the type as described above wherein the film additionally contains a metal selected from the group consisting of Au, Ag and Cu in the form of particles dispersed therein and having a particle size of at most 500 nm.

Abstract: A circuit and method for actively stabilizing the DC bias voltages applied to passive sections of a linearized directional coupler modulator. A reference electrical signal is applied to the active section of a linearized directional coupler modulator, thereby modulating an input optical beam. An optical detector is used at the output end of the modulator to monitor the modulated optical beam. The output of the detector is sent to one or more synchronous detectors that select the one or more harmonic frequency components that one wants to suppress. The synchronous detector output is sent to a filter that converts the harmonic frequency component to a DC bias voltage, which is integrated and used to bias the passive section of the modulator. The resulting negative-feedback loop minimizes the magnitude of the particular harmonic that is selected by the filter.

Abstract: A third-order nonlinear optical main chain polymer material contains a high .chi..sup.(3) component having no less than 3 but no more than 7 .pi.-conjugated bonding groups and having an electron donor in the main chain of the polymer through covalent bonds. The donor is preferably an alkylamino structure, more preferably a dialkylamino structure. Particularly preferred is a diethylamino structure. The high .chi..sup.(3) component is preferably a phenylene ring system of which phenylene rings are bonded through azo bonding groups with the phenylene rings and the azo bonding groups being positioned alternately. The polymer main chain is polyurethane or polyester. The third-order nonlinear optical main chain polymer material is prepared by polyaddition of a high .chi..sup.(3) compound, i.e., a precursor of the high .chi..sup.(3) component, having a hydroxyl group at each end with a diisocyanate compound or by polycondensation of the high .chi..sup.(3) compound with a dicarboxylic acid.

Abstract: A novel structure has, on a substrate a nonlinear optical thin film having a high .chi..sup.(3) value provided wherein metal fine particles are uniformly dispersed in a ferroelectric or highly dielectric matrix and heat treated whereby the metal fine particles and matrix are improved in crystallinity. The excitation wavelength can be substantially changed by a choice of the heat treating conditions. The crystallinity of the metal fine particles and matrix and .chi..sup.(3) value are improved by selecting a proper substrate or changing the heat treating procedure and conditions. The thin film is further improved in nonlinear optical properties, typically .chi..sup.(3) and .chi..sup.(3) /.alpha. values by using a perovskite type compound ABO.sub.3 having a specific A/B ratio as the matrix material and controlling film deposition conditions for improving the crystallinity of the matrix.

Abstract: The present invention is directed to organic materials that have the ability to double or triple the frequency of light that is directed through the materials. Particularly, the present invention is directed to the compound 4-[4-(2R)-2-cyano-7-(4'-pentyloxy-4-biphenylcarbonyloxy)phenylheptylidene) phenylcarbonyloxy]benzaldehyde, which can double the frequency of light that is directed through the compound. The invention is also directed to the compound (12-hydroxy-5,7-dodecadiynyl) 4'-[(4'-pentyloxy-4-biphenyl)carbonyloxy]-4-biphenylcarboxylate, and its polymeric form. The polymeric form can triple the frequency of light directed through it.

Abstract: Quasi-phase matched (QPM) second-harmonic (SH) generation in the reflection geometry is described. The SH intensity can be strongly enhanced by spatially modulating the optical properties of the nonlinear medium. This type of quasi-phase matching is demonstrated using an Al.sub.0.8 Ga.sub.0.2 As/GaAs heterostructure designed for .lambda.=1.06 .mu.m incident light. The SH light intensity generated in reflection from the heterostructure is enhanced 70 times relative to the SH response of a homogeneous GaAs wafer. A Fabry-Perot resonant cavity design employs this structure to make thin films with extremely high SH generation efficiencies. This is of particular interest used in vertical cavity surface emitting lasers (VCSELs).

Abstract: The nonlinear optical device of the present invention comprises a nonlinear optical element comprised of a chiral compound having a third-order nonlinearity. Further, the optical signal processing unit comprises a laser light source, the above-described nonlinear optical device, and a photodetector.

Abstract: A novel nonlinear optical thin film having a high .chi..sup.(3) value is provided wherein metal fine particles are uniformly dispersed in a ferroelectric or highly dielectric matrix and heat treated whereby the metal fine particles and matrix are improved in crystallinity. The excitation wavelength can be substantially changed by a choice of the heat treating conditions.The crystallinity of the metal fine particles and matrix and .chi..sup.(3) value are improved by selecting a substrate used or changing the heat treating procedure and heat treating conditions. By forming a portion having a lower content of metal fine particles in a surface portion on an upper and/or lower side of the matrix, the excitation wavelength can be substantially changed and precisely adjusted.

Abstract: When an optical signal is modulated at two modulation frequencies, third order intermodulation distortion (IMD) is eliminated by inducing an out-of-phase signal that is complementary to the modulated signal, and cross-coupling the two signals with each other to remove the third order terms. An optical beam in a first waveguide is electro-optically modulated and coupled with a second waveguide to induce the out-of-phase complementary beam therein. A second optical coupler is provided that cross-couples the beams in the two waveguides downstream from the first optical coupler. The optical coupling coefficients, the coupler lengths, and the differential between the optical propagation coefficients of the two waveguides within the first coupler are selected empirically to substantially negate third order IMD. The differential in propagation coefficients is established by the DC bias of the modulation signal.

Abstract: A compact solid state source of coherent laser light in the range of about 298 nm through about 355 nm utilizes a Nd:YAG or Nd:YLF laser to pump a tunable Ti:Al.sub.2 O.sub.3 laser. The beam from the Nd:YAG/Nd:YLF laser is then combined in a nonlinear optical crystal with the tunable beam from the Ti:Al.sub.2 O.sub.3 laser to provide a continuously tunable laser beam in the range of about 298 nm through about 355 nm.

Abstract: The present invention relates to electroactive compounds capable of undergoing a change in light absorption and refraction due to an applied electric field and a permanent change in refraction due to exposure to predetermined bands of optical radiation. The present invention also relates to electroactive compositions containing such electroactive compounds, electrooptical components comprised of such electroactive compositions and electrooptical devices comprised of such electrooptical components, as well as novel processes of making the same.

Abstract: A third-order nonlinear optical main chain polymer material contains a high .chi..sup.(3) component having no less than 3 but no more than 7 .pi.-conjugated bonding groups and having an electron donor in the main chain of the polymer through covalent bonds. The donor is preferably an alkylamino structure, more preferably a dialkylamino structure. Particularly preferred is a diethylamino structure. The high .chi..sup.(3) component is preferably a phenylene ring system of which phenylene rings are bonded through azo bonding groups with the phenylene rings and the azo bonding groups being positioned alternately. The polymer main chain is polyurethane or polyester. The third-order nonlinear optical main chain polymer material is prepared by polyaddition of a high .chi..sup.(3) compound, i.e., a precursor of the high .chi..sup.(3) component, having a hydroxyl group at each end with a diisocyanate compound or by polycondensation of the high .chi..sup.(3) compound with a dicarboxylic acid.

Abstract: A laser frequency conversion device employs a dual resonant optical cavity in which closed optical paths exist for both the pump beam and the generated beam. The optical cavity is designed so that the optical paths overlap the acceptance volume in phase space for coupling power from the pump beam into the output beam. At least one of the beams is pumped by an external laser which is aligned and mode matched to the cavity mode. The frequency of the pump laser or the cavity resonance modes is selected, generally by adjustment, to cause buildup of optical power at the pump frequency. The temperature and the angle of the nonlinear material are selected for phase match in the nonlinear interaction within the material. The frequencies of the modes near the output frequency are independently selected to cause buildup of optical power at the output frequency.

Abstract: A third-order nonlinear optical element showing wide employable wave-length range of input light, high speed operation and low light intensity of input light is disclosed.

Abstract: Nonlinear optical systems are provided which exhibit an enhanced nonlinear response to applied optical radiation. These systems are useful for processing radiation by nonlinear optical interactions, for example harmonic generation, mixing (sum and difference frequency generation), parametric oscillation, intensity dependent refractive index effects (focusing or lens formation) and perform various photonic functions (electro-optics). The systems utilize a materials system with an architecture in which inclusion components are distributed in a host component (preferably homogeneously). The host component has an optical response which varies nonlinearly with the amplitude of the optical field produced by the radiation applied to the composite material. The inclusion component is preferably particles which are less than a wavelength of the applied radiation in maximum dimension (diameter when the particles are spherical and length of major axis when the particles are generally ellipsoidal).

Abstract: This invention provides an optical medium and a process therefor wherein the medium exhibits third order nonlinear optical response and comprises a polymer with pendant groups having delocalized pi-electron character forming a charge transfer complex with dopant molecules. The optical medium is useful in optical devices, such as optical switches or light modulation devices as a component or as a coating. In other aspects, novel polymers and polymer complexes are disclosed.

Abstract: An organic optical logic device comprising, as a nonlinear optical medium, a crystal of organic molecules which are excited to a state of electronic excitation with an oscillator strength of at least 1.0 by visible or near-infrared radiation within a region of wavelengths of 0.4 to 1.3 .mu.m operates at room temperature with a low energy at great speed when the electronic excitation of the crystal generates excitons or exciton polaritons having a resonance wavelength of .lambda..sub.0 and the organic optical logic device is operated with a driving light having a wavelength of .lambda..sub.o -50 nm to .lambda..sub.o +50 nm.

Abstract: According to the present invention, there is provided a non-linear optical device comprising a non-linear optical medium comprising an organic compound, which remarkably improves the non-linear optical properties. The non-linear optical device according to the present invention is suited for the second and third harmonic generations, photomixing optical parametric oscillations, optical switches and optical bistable devices.

Abstract: An optical fiber for frequency conversion, has an annular index profile structure for obtaining zero order phase matching and optimum overlap between the fibers's resonant propagation modes, one propagating the wave w and the other the wave kw where 2.ltoreq.k.ltoreq.4 for at least one wavelength lying in the range 0.4 .mu.m to 2.6 .mu.m, with the index step .delta.n in the ring lying in the range 2.times.10.sup.-2 and 5.times.10.sup.-2, the inside radius r.sub.i of the ring lying in the range 0.5 .mu.m to 1.5 .mu.m, and the outside radius r.sub.e of the ring lying in the range 2 .mu.m to 3.5 .mu.m.