Kosuke Murate

The injection-seeded terahertz (THz) parametric generator (is-TPG) is one of the most high-power single-longitudinal mode THz-wave sources. Our system is less influenced by scattering, refraction, and multiple reflections by samples because it is a narrow-linewidth source, and the detection area of the THz parametric detector is large. Thus, it is suitable for nondestructive inspection of practical samples in the real world. In 2003, we reported on the development of a mail inspection system tha

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

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

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

We report a new method to temporally and spatially manipulate the pulse front tilt (PFT) intensity profile of an ultrashort optical pulse using a commercial microelectromechanical system, also known as a digital micromirror device (DMD). For our demonstration, we show terahertz generation in a lithium niobate crystal using the PFT pumping scheme derived from a DMD chip. The adaptive functionality of the DMD could be a convenient alternative to the more conventional grating required to generate a

Here, we introduce an injection-seeded terahertz (THz)-wave parametric generator (is-TPG) spectroscopic system and its application to nondestructive inspection through a packaging material with high attenuation. Recent technological innovations have dramatically improved is-TPG output. Combined with THz parametric detection, whereby detection is performed in the reverse process of generation, a spectrometer with an extremely high dynamic range has been achieved. THz spectroscopic imaging has ena

We achieved high identification accuracy of reagents hidden by thick shielding materials, by combining injection-seeded terahertz (THz) wave parametric generator measurements and machine learning analysis. The analysis performance of three methods, support vector machine (SVM), k-nearest neighbor, and random forest, was compared in an attempt to identify the optimal approach. SVM proved to be the best model. Conventional systems could only identify reagents through premeasured shields; however,

We have been using the principles of injection-seeded terahertz parametric generation (TPG) to develop the terahertz parametric amplifier (TPA) since 2014. Although we previously achieved amplification of 55 dB at 1.6 THz, amplification of lowfrequency terahertz waves (≤1 THz) or ultraweak inputs was difficult, because broadband terahertz waves (spontaneous TPG) were generated and interfered with amplification. Thus, we herein present a new technique that divides terahertz-wave amplification int

In this study, we propose a technique for identifying and imaging reagents through shielding over a wide dynamic range using a real-time terahertz (THz) spectroscopy system with multi-wavelength THz parametric generation/detection and machine learning. To quickly identify reagents through shielding, the spectral information of the "detection Stokes beam" is used for reagent recognition via machine learning. In general THz wave-based reagent identification, continuous spectra are acquired and ana

In this study, we developed a multiwavelength spectroscopic measurement system using a pulse burst-pumped injection-seeded terahertz (THz)-wave parametric generator (is-TPG). Real-time spectroscopy using multiwavelength simultaneous generation has been demonstrated; however, the ability to make quantitative measurements with this method has been limited by the gain competition between wavelengths. In this study, we divided the pump beam into multiple paths and created pulse bursts with nanosecon

Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text K. Murate, K. Imayama, S. 'i. Hayashi, and K. Kawase, "Wider tunability of an injection-seeded THz parametric generator," in Nonlinear Optics, OSA Technical Digest (online) (Optica Publishing Group, 2015), paper NTu1B.2. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article

YAG (injection seeded THz Parametric Generator: is-TPG) 1,2) (THz-TDS) 3) ( ) 4-6) 2003is-TPG (Terahertz Parametric Oscillator : TPO) 7) 4,5) TPO 4 0.1 mm is-TPG 100 kW 2) 0.4-5.0THz 8,9) LiNbO 3 10) 10 2,11) -60 dB (Fig. 1) 6) -70 dB3CT (Fig. 2) 12)

In this study, we demonstrated a low-noise, high-gain terahertz (THz) parametric amplifier (TPA). The TPA is divided into two parts: a preamplifier and a main amplifier. In this configuration, wavelength conversion to near-infrared (NIR) light is performed by the preamplifier. The NIR light has different generation angles for each wavelength to satisfy the phase-matching conditions; thus, broadband noise can be spatially removed using an iris. Converting the THz wave again in the main amplifier,

To realize practical applications of terahertz (THz) waves, it is crucial to establish high-speed and real-time spectroscopic techniques. Although single-shot spectroscopy based on THz time-domain spectroscopy (THz-TDS) has been extensively studied, reports on fast spectroscopy using wavelength-tunable THz sources remain limited. In this paper, we overview the characteristics of various wavelength-tunable sources and introduce recent advancements in high-speed and single-shot THz spectroscopy ba