Abstract: A ring optical resonator and one or more input optical waveguides are arranged on a substrate, and are arranged and positioned to establish evanescent optical coupling between them. The ring optical resonator, the substrate, or both include one or more nonlinear optical materials. To detect an electromagnetic signal at frequency ?EM incident on the resonator, an input optical signal at frequency ?IN propagates along the waveguide and around the resonator. The incident electromagnetic signal and the input optical signal generate one or more sideband optical signals at corresponding optical sideband frequencies ?SF=?IN+?EM or ?DF=?IN??EM. To generate an electromagnetic signal to propagate away from the resonator, input optical signals at frequencies ?IN1 and ?IN2 propagate along one or more waveguides and around the resonator and generate the electromagnetic signal incident at frequency ?EM=|?IN1??IN2|.

Abstract: A ring optical resonator and one or more input optical waveguides are arranged on a substrate, and are arranged and positioned to establish evanescent optical coupling between them. The ring optical resonator, the substrate, or both include one or more nonlinear optical materials. To detect an electromagnetic signal at frequency ?EM incident on the resonator, an input optical signal at frequency ?IN propagates along the waveguide and around the resonator. The incident electromagnetic signal and the input optical signal generate one or more sideband optical signals at corresponding optical sideband frequencies ?SF=?IN+?EM or ?DF=?IN??EM. To generate an electromagnetic signal to propagate away from the resonator, input optical signals at frequencies ?IN1 and ?IN2 propagate along one or more waveguides and around the resonator and generate the electromagnetic signal incident at frequency ?EM=|?IN1??IN2|.

Abstract: A linearly polarized upconverting optical signal at optical frequency ?OPT and a propagating input signal at frequency ?GHz are combined by an input beam combiner to copropagate through a nonlinear optical medium and generate upconverted optical signals at one or both sum or difference frequencies ?SUM=?OPT+?GHz or ?DIFF=?OPT??GHz. The orthogonally polarized upconverting and upconverted optical signals are separated by a polarizer, and the upconverted optical signal is preferentially transmitted to a detection system by an optical filter. The input signal is modulated to encode transmitted information, and that modulation is imparted onto the upconverted optical signal. The detection system includes one or more photodetectors, receives the upconverted optical signal, and generates therefrom electrical signals that are modulated to encode the transmitted information.

Abstract: A linearly polarized upconverting optical signal at optical frequency ?OPT and a propagating input signal at frequency ?GHz are combined by an input beam combiner to copropagate through a nonlinear optical medium and generate upconverted optical signals at one or both sum or difference frequencies ?SUM=?OPT+?GHz or ?DIFF=?OPT??GHz. The orthogonally polarized upconverting and upconverted optical signals are separated by a polarizer, and the upconverted optical signal is preferentially transmitted to a detection system by an optical filter. The input signal is modulated to encode transmitted information, and that modulation is imparted onto the upconverted optical signal. The detection system includes one or more photodetectors, receives the upconverted optical signal, and generates therefrom electrical signals that are modulated to encode the transmitted information.

Abstract: An optical parameter oscillator (OPO) is pumped at pump wavelength ?P to resonate at signal wavelength ?S. The OPO produces idler radiation at terahertz frequencies ?THz=c/?P?c/?S. The pump, signal, and idler radiation are substantially collinear.

Abstract: An optical parameter oscillator (OPO) is pumped at pump wavelength ?P to resonate at signal wavelength ?S. The OPO produces idler radiation at terahertz frequencies ?THz=c/?P?c/?S. The pump, signal, and idler radiation are substantially collinear.

Abstract: A cw terahertz image beam is upconverted by a nonlinear optical process (e.g., sum- or difference-frequency generation with a near IR cw upconverting beam). The upconverted image is acquired by a near IR image detector. The bandwidths and center wavelengths of the terahertz image beam and the upconverting beam are such that wavelength filtering can be employed to permit an upconverted image beam to reach the detector while blocking or substantially attenuating the upconverting beam.

Abstract: A cw terahertz image beam is upconverted by a nonlinear optical process (e.g., sum- or difference-frequency generation with a near IR cw upconverting beam). The upconverted image is acquired by a near IR image detector. The bandwidths and center wavelengths of the terahertz image beam and the upconverting beam are such that wavelength filtering can be employed to permit an upconverted image beam to reach the detector while blocking or substantially attenuating the upconverting beam.

Abstract: A terahertz image beam is upconverted by a nonlinear optical process (e.g., sum- or difference-frequency generation with a near IR upconverting beam). The upconverted image is acquired by a near IR image detector. The terahertz image beam and upconverting beam comprise trains of picosecond pulses. The bandwidths and center wavelengths of the terahertz image beam and the upconverting beam are such that wavelength filtering can be employed to permit an upconverted image beam to reach the detector while blocking or substantially attenuating the upconverting beam.

Abstract: A terahertz image beam is upconverted by a nonlinear optical process (e.g., sum- or difference-frequency generation with a near IR upconverting beam). The upconverted image is acquired by a near IR image detector. The terahertz image beam and upconverting beam comprise trains of picosecond pulses. The bandwidths and center wavelengths of the terahertz image beam and the upconverting beam are such that wavelength filtering can be employed to permit an upconverted image beam to reach the detector while blocking or substantially attenuating the upconverting beam.

Abstract: A method comprises spatially selectively irradiating in a predetermined pattern with an output beam of a laser system an interface between a polymer substrate and a metal film on the polymer substrate. The polymer substrate is substantially transparent to the output beam of the laser system; the metal film absorbs a substantial fraction of the output beam. Laser system output comprises a sequence of pulses. Beam size at the polymer/metal interface, pulse energy, and pulse duration are selected so that each pulse from the laser system that irradiates an area of the polymer/metal interface substantially completely removes by ablation the metal film from at least a portion of the irradiated area without substantially altering the surfaces or bulk of the polymer substrate and without leaving on the polymer substrate or on remaining areas of the metal film substantial residue of metal that resolidified after being melted by the laser irradiation.

Abstract: A synchronously pumped optical parametric oscillator (OPO) comprises a nonlinear optical medium positioned in an optical resonator (e.g., a ring resonator) and is pumped by a pump laser source. A first arrangement includes a positioning mechanism for translating the nonlinear optical medium so OPO resonant modes propagate through one of multiple longitudinal regions arranged for differing odd orders of quasi-phase-matching. A second arrangement includes a pump fiber laser oscillator stretched to adjust its repetition rate to match that of the OPO. A third arrangement includes a time-domain-multiplexer (TDM) fiber loop between a pump fiber laser oscillator and fiber laser amplification stage(s). The TDM loop increases the pump repetition rate to enable increased average pump power without increased peak power.

Abstract: A synchronously pumped optical parametric oscillator (OPO) comprises a nonlinear optical medium positioned in an optical resonator (e.g., a ring resonator) and is pumped by a pump laser source. A first arrangement includes a positioning mechanism for translating the nonlinear optical medium so OPO resonant modes propagate through one of multiple longitudinal regions arranged for differing odd orders of quasi-phase-matching. A second arrangement includes a pump fiber laser oscillator stretched to adjust its repetition rate to match that of the OPO. A third arrangement includes a time-domain-multiplexer (TDM) fiber loop between a pump fiber laser oscillator and fiber laser amplification stage(s). The TDM loop increases the pump repetition rate to enable increased average pump power without increased peak power.

Abstract: A synchronously pumped optical parametric oscillator (OPO) comprises a nonlinear optical medium positioned in an optical resonator (e.g., a ring resonator) and is pumped by a pump laser source. A first arrangement includes a positioning mechanism for translating the nonlinear optical medium so OPO resonant modes propagate through one of multiple longitudinal regions arranged for differing odd orders of quasi-phase-matching. A second arrangement includes a pump fiber laser oscillator stretched to adjust its repetition rate to match that of the OPO. A third arrangement includes a time-domain-multiplexer (TDM) fiber loop between a pump fiber laser oscillator and fiber laser amplification stage(s). The TDM loop increases the pump repetition rate to enable increased average pump power without increased peak power.

Abstract: A method comprises spatially selectively irradiating in a predetermined pattern with an output beam of a laser system an interface between a polymer substrate and a metal film on the polymer substrate. The polymer substrate is substantially transparent to the output beam of the laser system; the metal film absorbs a substantial fraction of the output beam. Laser system output comprises a sequence of pulses. Beam size at the polymer/metal interface, pulse energy, and pulse duration are selected so that each pulse from the laser system that irradiates an area of the polymer/metal interface substantially completely removes by ablation the metal film from at least a portion of the irradiated area without substantially altering the surfaces or bulk of the polymer substrate and without leaving on the polymer substrate or on remaining areas of the metal film substantial residue of metal that resolidified after being melted by the laser irradiation.

Abstract: A method comprises spatially selectively irradiating in a predetermined pattern with an output beam of a laser system an interface between a polymer substrate and a metal film on the polymer substrate. The polymer substrate is substantially transparent to the output beam of the laser system; the metal film absorbs a substantial fraction of the output beam. Laser system output comprises a sequence of pulses. Beam size at the polymer/metal interface, pulse energy, and pulse duration are selected so that each pulse from the laser system that irradiates an area of the polymer/metal interface substantially completely removes by ablation the metal film from at least a portion of the irradiated area without substantially altering the surfaces or bulk of the polymer substrate and without leaving on the polymer substrate or on remaining areas of the metal film substantial residue of metal that resolidified after being melted by the laser irradiation.

Abstract: A source of terahertz radiation at a fundamental terahertz frequency is tunable over a fundamental terahertz frequency range, and is coupled into a first waveguide. The first waveguide supports only a single transverse spatial mode within the fundamental terahertz frequency range. A solid-state frequency multiplier receives from the first waveguide the terahertz radiation and produces terahertz radiation at a harmonic terahertz frequency. A second waveguide receives the harmonic terahertz radiation. The tunable terahertz source can comprise a backward wave oscillator with output tunable over about 0.10-0.18 THz, 0.18-0.26 THz, or 0.2-0.37 THz. The frequency multiplier can comprises at least one varistor or Schottky diode, and can comprise a doubler, tripler, pair of doublers, doubler and tripler, or pair of triplers. The terahertz source can be incorporated into a terahertz spectrometer or a terahertz imaging system.

Abstract: A method for generating THz radiation comprises illuminating a semiconductor crystal with an optical pulse train. The semiconductor crystal comprises alternating parallel crystal domains, with each domain having a crystal orientation inverted with respect to adjacent domains. The optical pulse train propagates substantially perpendicularly relative to domain boundaries in the semiconductor crystal. The THz radiation is generated from the optical pulse train by optical down-conversion mediated by the semiconductor crystal. Optical path lengths through the crystal domains at least in part determine a frequency of the generated THz radiation. THz generation efficiency may be enhanced by placing the semiconductor crystal within an external resonant cavity, by placing the semiconductor crystal within a laser cavity, or by placing the semiconductor crystal within an OPO cavity. The semiconductor crystal may comprise zinc-blende, III-V, or II-VI semiconductor.

Abstract: Lasers comprising a substrate and a layer of organic material over the substrate. The organic material includes host and dopant materials that result in the laser emission of a desired color when pumped by optical pump energy. Host materials include CBP and tris-(8-hydroxyquinoline) aluminum, which when combined with dopant materials such as coumarin-47, coumarin-30, perylene, rhodamine-6G, DCM, DCM2, and pyrromethane-546 result in the efficient lasing of colors such as blue, green and yellow.