A5102728591- Terahertz technology and applications
- Photonic and Optical Devices
- Spectroscopy and Laser Applications
- Photorefractive and Nonlinear Optics
- Solid State Laser Technologies
- Acoustic Wave Resonator Technologies
- Superconducting and THz Device Technology
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Gyrotron and Vacuum Electronics Research
- Metamaterials and Metasurfaces Applications
- Semiconductor Lasers and Optical Devices
- Semiconductor Quantum Structures and Devices
- Laser-Matter Interactions and Applications
- Photonic Crystals and Applications
- Optical and Acousto-Optic Technologies
- Microwave Engineering and Waveguides
- Advanced Antenna and Metasurface Technologies
- Advanced Optical Sensing Technologies
- Millimeter-Wave Propagation and Modeling
- Optical Polarization and Ellipsometry
- Plant Pathogens and Resistance
- Antenna Design and Optimization
- Leaf Properties and Growth Measurement
- Microwave and Dielectric Measurement Techniques
RIKEN Center for Advanced Photonics
2015-2024
Tohoku Institute of Technology
2023-2024
Nitto RIKEN (Japan)
2011-2022
RIKEN
2011-2021
Topcon (Japan)
2018
Tohoku University
2018
Nippon Soken (Japan)
2011-2015
RIKEN Advanced Science Institute
2012-2014
Chiba University
2005-2010
Kyoto University
1998
The hottest frequency region in terms of research currently lies the 'frequency gap' between microwaves and infrared: terahertz waves. Although new methods for generating radiation have been developed, most sources cannot generate high-brightness beams. Here we demonstrate generation ultrabright waves (brightness ~0.2 GW/sr·cm2, brightness temperature ~1018 K, peak power >50 kW) using parametric wavelength conversion a nonlinear crystal; this is brighter than many specialized such as...
Tunable terahertz (THz)-wave absorption spectroscopy is a promising technique to detect trace gases suspended in ambient air owing their strong fingerprints the THz-wave spectral region. Here, we present spectroscopic gas detection platform based on frequency-tunable injection-seeded parametric generator and compact multipass cells. Using 1.8-m-path-length cell, detected gas-phase methanol (CH 3 OH) down concentration of 0.2 ppm at 1.48-THz transparent atmospheric window. We also developed...
We developed a difference frequency generation (DFG) source with an organic nonlinear optical crystal of DAST or BNA selectively excited by dual-wavelength β-BaB(2)O(4) parametric oscillator (BBO-OPO). The BBO-OPO can independently oscillate two lights different wavelengths from 800 to 1800 nm in cavity. THz-wave using each covers ultrawide range 1 30 THz inherent intensity dips absorption modes. reduced outputs be improved switching over the crystals adequately tuned pump BBO-OPO.
This Letter describes a novel metamaterial design by employing off-resonance and in-resonance excitation for high-transmission terahertz-wave quarter-wave plate (QWP). The device is demonstrated with thin film double-layer split ring resonators (SRRs). Different from usual resonant device, here we the work frequency off inductor-capacitor (LC) resonance TE mode, while in dipole TM mode to obtain artificial birefringence. Rectangular SRRs this provide choice optimize excitation, assist high...
Backward optical parametric oscillation has attracted attention for cavityless spectral narrowband generation based on perfect photon conversion. Few demonstrations have shown its potential from the aspect of nonlinear photonics; therefore, mechanisms momentum conservation among interacting light waves been concealed by restricted configuration under phase-matching condition periodically poled structures. Here, we unveil a tunable mechanism in terahertz region active control condition. The...
We demonstrated high-repetition-rate (sub-MHz) MW pulse generation by combining a picosecond phase conjugate laser system based on diode-side-pumped Nd:YVO(4) bounce amplifier with selector RbTiOPO(4) electro-optical modulator. Peak output powers in the range of 2.8-6.8 at repetition frequency 0.33-1.0 MHz were achieved an extraction efficiency 34-35%.
Real-time terahertz (THz) wave imaging has wide applications in areas such as security, industry, biology, medicine, pharmacy, and the arts. This report describes real-time room-temperature THz by nonlinear optical frequency up-conversion an organic 4-dimethylamino-N'-methyl-4'-stilbazolium tosylate (DAST) crystal, with high resolution reaching diffraction limit. THz-wave images were converted to near infrared region then captured using InGaAs camera a tandem system. The of system was...
We have experimentally determined the terahertz- (THz-) wave parametric gain of stimulated Raman scattering (SRS) by phonon-polaritons in $\mathrm{LiNb}{\mathrm{O}}_{3}$. Our approach is based on ultrabright THz-wave generation from SRS under Brillouin suppression with subnanosecond pump pulses. To obtain frequency dependence gain, we measured crystal-length output directly using a surface-coupling configuration. found that product and threshold crystal length constant throughout tuning...
We report on the generation of high-brightness (high peak power and narrow linewidth) continuously tunable subterahertz waves by optical parametric wavelength conversion using lithium niobate as a nonlinear crystal. The were achieved expanding interaction volume pumping beam idler wave, well during injecting seeding into wave. could tune wavelengths generated controlling angle difference between injection beams to satisfy noncollinear phase-matching conditions. (maximum output power, range...
Thin terahertz (THz)-wave optical components are fundamentally important for integrated THz-wave spectroscopy and imaging systems, especially phase manipulation devices. As described herein, a thin shifter was developed using flexible film metamaterial with high transmission polarization independent properties. The unit structure employs double-layer un-split ring resonators (USRRs) designed distance between the two layers to obtain retardance of π/2, thus constituting shifter. design keeps...
Using a nonlinear optical mixing known as frequency up-conversion process, we demonstrate an cross-correlation technique for the detection and characterization of sub-nanosecond (sub-ns) terahertz (THz)-wave pulses. A monochromatic THz-wave pulse from injection-seeded parametric generator (is-TPG) was mixed with near-infrared (NIR) pump to generate NIR idler in trapezoidal-prism-shaped MgO-doped lithium niobate crystal under noncollinear phase-matching condition. By measuring pump-energy...
Abstract An overview on current trends in stimulated Brillouin scattering and optical phase conjugation is given. This report based the results of “Second International Workshop conjugation” held Potsdam/Germany September 2007. The properties are presented for compensation distortions combination with novel laser technology like ceramics materials but also e.g., stabilization, beam combination, slow light. Photorefractive nonlinear mirrors resonant refractive index gratings addressed as...
Injection-seeded terahertz (THz)-wave parametric generation pumped by subnanosecond pulses was demonstrated as an exploration of the effective pump pulse width. In experiments, sources with different widths 35-850 ps were used. The relationship between undesirable effect stimulated Brillouin scattering (SBS) and THz-wave output in LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> analyzed. transient on SBS not actualized around...
A widely tunable terahertz (THz)-wave generation that has a high repetition rate and narrow line width is demonstrated in this paper by injection-seeded THz-wave parametric (is-TPG) MgO:LiNbO3 crystal. By pumping the crystal using passively Q-switched neodymium-doped yttrium vanadate microchip laser with time duration of 140 ps an average power up to 5 W, output 30 μW, peak 4 pulse 73 ps, pulse-repetition frequency 100 kHz obtained. To prevent damage photorefractive crystal, constraints on...
Engineered quasi-phase-matching in a periodically poled nonlinear crystal has enabled backward optical parametric oscillators, where pump photon is down-converted to counterpropagating signal and idler photons without an cavity. Here, we demonstrate injection-seeded terahertz-wave oscillator (BW-TPO) based on slant-strip-type lithium niobate crystal. A continuous-wave single-frequency laser used the BW-TPO pumped by sub-nanosecond 1064.4-nm pulses provide injection seed beam for...
We demonstrated >80 W picosecond output at a pulse repetition frequency of 100 MHz from dual Nd:YVO(4) amplifier laser system consisting phase-conjugate bounce combined with second diode-side-pumped amplifier. The exhibited high quality spatial form M(2) < 1.8 and duration (FWHM) 9.2 ps. A peak power >7.4 MW an average 78.5 was also achieved 1.0 MHz.
We firstly obtained organic N-benzyl-2-methyl-4-nitroaniline (BNA) single crystals using solution growth method. The crystal quality by method was much better than that of grown the Bridgman Furthermore, difference frequency generation (DFG) in solution-grown BNA, we generated ultra-wideband tunable THz radiation.
The sensitive detection of terahertz (THz)-wave radiation from compact sources at room temperature is crucial for real-world THz-wave applications. Here, we demonstrate the nonlinear optical continuous-wave (CW) resonant tunneling diodes (RTDs) 0.58, 0.78, and 1.14 THz. up-conversion process in a MgO:LiNbO3 crystal under noncollinear phase-matching condition offers efficient wavelength conversion THz wave to near-infrared (NIR) that detected using commercial NIR photodetector. minimum limit...
We propose a slant-stripe-type periodically poled LiNbO3 crystal for the construction of practical quasi-phase-matched (QPM) device terahertz (THz) detection. A minimum detectable THz-wave energy 25 fJ/pulse is demonstrated, and linear input-output property with dynamic range 60 dB achieved. The working frequency 0.15 THz detection obtained, central sensitivity can be controlled by design structure. using this QPM promising technique that may allow coherent photon.
The importance of terahertz (THz) wave techniques has been demonstrated in various fields, and the range applications is now expanding rapidly. However, practical implementation THz science to solve real-world problems restricted due lack not only convenient high power emitters sensitive detectors but also efficient quasi-optical active devices such as amplifiers. In this work, we demonstrate direct amplification waves room temperature using magnesium oxide-doped lithium niobate (MgO:LiNbO3)...
By applying the frequency conversion technique to 4-dimethylamino-N-methyl-4-stilbazolium tosylate crystal, a monochromatic terahertz (THz) measurement system, including both generation and detection, has been developed over quite broad band, from 1.85 30 THz. In case of upconversion detection THz waves, for first time, we used gratings instead filters tackle tough phase-matching conditions broadband operations. synchronizing rotation two extract upconverted signal, infrared (IR) pumping...
We investigated design issues for the power scaling of a pico-second Nd:YVO(4) master-oscillator amplifier system with photorefractive phase-conjugate mirror by using standard beam propagation analysis. also demonstrated 25 W diffraction-limited output. A corresponding extraction efficiency 31 % was achieved.
Real-time terahertz (THz) wave imaging has wide applications in areas such as security, industry, biology, medicine, pharmacy, and arts. In this letter, we report on real-time room-temperature THz by nonlinear optical frequency up-conversion organic 4-dimethylamino-N′-methyl-4′-stilbazolium tosylate crystal. The active projection-imaging system consisted of (1) generation, (2) THz-near-infrared hybrid optics, (3) up-conversion, (4) an InGaAs camera working at 60 frames per second. pumping...