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...

Terahertz spectroscopy has rapidly progressed, and is being applied to various research fields as a new non-invasive examination method. Scientific analysis important for the conservation of art, it can help reveal history work determine proper materials its restoration. Mid-infrared X-ray are currently used identify organic inorganic materials, respectively. expected composites themselves, give clear direct information art conservation. We have collected terahertz spectra historical modern...

A surface-wave sensor based on the resonant transmission characteristics of metal hole arrays is demonstrated in terahertz (THz) region. Since frequency peak a array, which corresponds to surface waves, particularly sensitive refractive index vicinity surface, very small change substances attached can be detected by monitoring spectrum. By attaching layer substance (thickness t < 5 microm) much thinner than wavelength THz wave (lambda(THz) = 1 mm at 0.3 THz) we that existence such amount...

We report on the development of a high-peak-power, single-longitudinal-mode and tunable injection-seeded terahertz-wave parametric generator using MgO:LiNbO3, which operates at room temperature. The high peak power (> 120 W) is enough to allow easy detection by commercial calibrated pyroelectric detectors, spectral resolution (< 10 GHz) Fourier transform limit sub-nanosecond pulse. tunability (1.2-2.8 THz) small footprint size (A3 paper, 29.7 × 42 cm) are suitable for variety applications.

Terahertz (THz) technology is a focus of attention in research on applied optics. We have THz spectroscopy and THz-imaging method to text recognition medieval manuscript made from sheepskin. Based the database which contains more than 200 spectra art materials, red ink was estimated as Cinnabar. The stains were successfully distinguished by THz-Time Domain Spectroscopy (TDS) imaging with component spatial pattern analysis. can be used non-invasive analysis for conservation science cultural...

We demonstrate a highly sensitive imaging method combined terahertz time-domain spectroscopy and an interference effect for label-free protein detection on polyvinylidene difluoride membrane. The is based uses effect. Biotin linked to the membrane using poly ethylene glycol or methyl ether prevent it from being washed off. Binding of biotin with streptavidin then observed by measuring signal change due variation refractive index. binding in gradually decreasing concentrations, down 27 ng...

A wideband, wavelength tunable, spectrally flat terahertz (THz) spectrometer with a dynamic range in excess of 70 dB was demonstrated. The emission THz-wave achieved using an injection-seeded THz parametric generator (is-TPG), and detection nonlinear optical conversion, both magnesium-oxide-doped lithium niobate crystal. This system has potential applications non-destructive sensing imaging wide variety materials.

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...

Abstract In this paper, we report the improvement of frequency tuning range an injection-seeded terahertz (THz)-wave parametric generator (is-TPG). A significant previous limitation was high absorption coefficient in higher-frequency region a MgO:LiNbO 3 crystal. Here, inclined crystal slightly, so that fraction pump beam internally reflected at THz-wave exit surface configuration, it easier for THz wave to reach surface, because center core closer surface. As result, upper limit increased...

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...

This study investigated the effects of millimeter wave (MMW) irradiation with a wide range frequencies on proliferation and activity normal human skin fibroblast (NB1RBG) glioblastoma (A172) cells. Very few studies have focused low-power, long-term cells widely tunable source. Our research examined non-thermal exposed to radiation at low power from 70 GHz 300 GHz. A MMW source was set within cell culture incubator. To avoid effect heat generation due irradiation, intensity maintained below...

We have enhanced the tunability of a terahertz-wave parametric generator using MgO:LiNbO3 pumped by subnanosecond, passively Q-switched, microchip Nd:YAG laser. This pump source allows high-intensity pumping without damage to nonlinear crystal and generates narrow linewidth tunable terahertz wave with injection seeding an external cavity diode laser for idler wave. The causes gain curve broadening generation, especially in high-frequency region. obtained output tuning range 0.9-3 THz...

In this study, the simultaneous generation of multiwavelength terahertz (THz) waves by an injection-seeded THz parametric generator (is-TPG) was achieved for first time. The output and stability were equivalent to those generated via a single-wavelength is-TPG. Spatial separation frequencies high-sensitivity detection converting near-infrared beams. Furthermore, one-pulse spectroscopy saccharides realized, dynamic range more than 60 dB obtained. results demonstrated possibility using is-TPG...

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...

One of the most important features for ferroelectric material is fast write at low voltage. This feature used in a 256 kb nonvolatile memory that operates 3 V power supply with read/write time 100 ns. Active current mA 200 ns cycle battery operation. The cell consists 1 transistor and capacitor per bit (1T1C) permitting high level integration. For low-voltage low-power operation, use made preset reference-cell circuit, wordline boost circuits boosting divided-cell plate circuit.< <ETX...

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)...

Broadband terahertz (THz) waves were generated by optical parametric processes based on laser light scattering from the polariton mode of a nonlinear crystal. By using oscillation MgO-doped LiNbO3 crystal pumped nanosecond Q-switched Nd:YAG laser, we have realized broadband, high-energy and compact THz-wave source. We report development generator (TPG) small pump source with short pulse width top-hat beam profile. These characteristics permit high-intensity pumping especially close to output...

Attenuated total reflection (ATR) spectroscopy in the terahertz (THz) region was used to measure spectra of water, aqueous glycine solution, and powder between 0.5 12THz. By subtracting absorption spectrum we obtained clear peaks for dissolved at 2.1, 5.2, 9.3THz. In addition, observed that frequencies these differed from powder. This indicates low-frequency vibrational mode molecules changes with hydrogen bonding H2O molecules.

Recent progress has been made in the development of terahertz (THz) waves for practical applications. Few studies that have assessed biological effects THz reported, and data currently available regarding safety is inadequate. In this study, effect wave exposure on two cultured cells was using a widely tunable source with 0.3–0.6 frequency range, which can be used increased one GHz increments. The applied to were weak enough such any thermal could disregarded. influence both proliferative...

A technique is presented for the measurement of absorption properties liquids in terahertz wave range, based on interaction between liquid and evanescent covering surface a cylindrical waveguide made high-resistivity silicon. The propagates inside as fundamental EH11 mode. presence medium around silicon rod has measurable effect overall end-to-end transmission waveguide. As demonstration, we report measurements D-glucose aqueous solution with concentration ranging from 0% to 45%, using...

We report a terahertz (THz) wave amplifier based on optical parametric processes in magnesium-oxide-doped lithium niobate (MgO:LiNbO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) crystals. The operates at room temperature and has gain of 55 dB. non-linear crystals used for the purposes emission amplification THz waves are pumped separately using microchip laser, which leads to an enhancement comparison with existing approaches.

We are studying some novel steps toward real-life applications of terahertz wave. In this paper, we introduce two THz sensing methods for ensuring the safety and security lives people, such as, i) Nondestructive detection illicit drugs using spectral fingerprints, ii) Label-free detections protein-protein interactions allergy test.