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We developed a tunable mid-infrared optical vortex output from an optical vortex parametric laser formed of a1 μm optical vortex pumped KTiOPO4 optical parametric oscillator (OPO) in combination with a AgGaSe2 difference frequency generator (DFG). The wavelength of the optical vortex output was oscillated within a mid-infrared wavelength region of 6–18 μm.
The cornea is one of the most important external structure of the human eye. Its transparency is an important factor for visual function and depends on the tissue hydration. For cornea hydration sensing we use terahertz reflectometer based on difference frequency generation of a pair of continuous semiconductor lasers. Spectral sensitive measurements are obtained by fine frequency tuning of terahertz...
A new millimeter-wave (MMW) signal generation device using a rectangular waveguide and second order nonlinear optical effect is proposed. Using a T-shaped rectangular waveguide with a suspended LiTaO3 crystal, adiabatic MMW signal injection into the waveguide is obtainable through optical difference frequency generation in the crystal. This device is easy for coupling to standard rectangular waveguide...
Carbon monoxide laser systems emitting laser pulses with duration from milliseconds down to nanoseconds were developed and applied for the frequency conversion of CO laser spectrum due to sum and difference frequency generation in nonlinear crystals.
Millimeter-wave signal generation devices using difference frequency generation based on the second order nonlinear optical effect in rectangular waveguide circuits were studied in detail theoretically and experimentally. 60GHz-band signals were successfully obtained from fabricated proto-type devices using a straight rectangular waveguide with z-cut LiTaO3 crystal. T-branching waveguide devices are...
Periodically poled congruent lithium tantalite (PPCLT) and periodically poled congruent lithium niobate (PPCLN)-based quasi phase matched (QPM) difference frequency generation (DFG) conversion systems are developed for inclusion in a mid-IR spectrometer providing a wavelength tunable and efficient conversion solution. Using two continuous wave (CW) fiber lasers the conversion efficiency of DFG CLT...
Theoretical analyses and simulations of terahertz generation based on difference frequency generation in nonlinear crystal ZnTe are presented in this paper. Owing to the phase mismatching and crystal absorption, the crystal length has great influence on the spectral width and determines the central frequency of the terahertz radiation. The dependence of the temporal and spectral waveforms on the pump...
In this paper, theoretical analysis and numerical simulation are expatiated distinctly according to the conversion principle and structure model of SP-cSHG+DFG-DC-AOWC (Single Pass All Optical Wavelength Converter Based on Cascaded Second Harmonic Generation and Difference Frequency Generation with Double Conversion Configuration) relative to SP-cSHG+DFG-DC-AOWC (Single Pass All Optical Wavelength...
In this paper, the comparison of theoretical analysis and numerical simulation in conversion efficiency, bandwidth, frequency difference and multichannel propagation are expatiated distinctly according to the conversion principle and structure model of SP-cSHG+DFG-DC-AOWC (Single Pass All Optical Wavelength Converter Based on Cascaded Second Harmonic Generation and Difference Frequency Generation...
We have proposed a new DFG-based signal generation device in a LiTaO3 rectangular waveguide. 15 GHz signal was successfully generated from the fabricated device. In this paper, its application for higher-frequency signal generation is discussed.
We demonstrate flexible waveband conversion covering the entire C-band using 8-peak-multiple-QPM-LN waveguides to solve the problem of wavelength contention in a waveband-switching node. The phase-transparent conversion of a 43 Gb/s RZ-DQPK waveband signal is also confirmed.
A monochromatic THz radiation source with broadband tunability utilizing N-benzyl-2-methyl-4-nitroaniline (BNA) crystal has been developed. BNA quality was improved by applying solution growth method instead of melt method. BNA-THz source using difference frequency generation was further optimized.
We generated ultrabroadband coherent infrared wave with a frequency range of 0.1-200 THz using difference frequency generation in crystals of DAST, GaSe, and dipole radiation from a photoconductive antenna. Also we detected the wave by time domain spectroscopy with a photoconductive antenna.
By stacking two GaP plates, we have improved the THz peak power from 433 W to 1.36 kW based on difference-frequency generation, corresponding to an enhancement by two orders of magnitude over the previous result.
We produce tunable (1.3-3THz) narrow-band THz-wave output with >130μW average power in periodically-inverted GaAs inside a near-degenerate type-0 PPLN OPO containing thin YAG etalon for spectral control, synchronously pumped by a 1064-nm 10-ps Yb-fiber laser.
We propose a practical implementation for single-photon down conversion based on difference frequency generation by a nonlinear crystal. A theoretical model is presented, where the quantum noise sources, relevant to the process, are identified.
Wavelength converters based on double-pass quasi-phase matched cascaded sum and difference frequency generation in lossy lithium niobate waveguides with a large pump wavelength difference are numerically evaluated assuming pump wavelength detuning to flatten the response.
Terahertz (THz) wave generation based on nonlinear frequency conversion is promising way for realizing a tunable monochromatic bright THz-wave source. Such a development of efficient and wide tunable THz-wave source depends on discovery of novel brilliant nonlinear crystal. Important factors of a nonlinear crystal for THz-wave generation are, 1. High nonlinearity and 2. Good transparency at THz frequency...
Tunable narrow band terahertz (THz) pulses were generated in periodically poled lithium niobate and lithium tantalite at 0.6 and 1.4 THz with bandwidth of 20 GHz. The generation THz frequency and intensity were strongly depending on temperature of crystal and pump laser spectral bandwidth.
We have developed a continuous wave (CW) terahertz (THz) wave generation by near infrared laser diode (NIR-LD) pumping based on non-collinear phase-matched difference frequency generation (DFG) in a GaP crystal. The THz output power is improved at suitable length of GaP and NIR beam spot size. By using this generator, we measured spectra with high resolution.
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