We constructed a widely and continuously tunable terahertz frequency synthesizer traceable to hydrogen maser linked coordinated universal time. Photomixing of two optical synthesizers, the via dual combs, gave this THz uncertainty 10⁻¹². To demonstrate potential wide continuous tunability in synthesizer, we tuned its output up 50 GHz discretely 1.26 F-band while maintaining unprecedented by using uni-traveling-carrier photodiode as photomixer. This will be powerful tool for broadband,...

We demonstrate a high dynamic range (DR) Fourier-transform-based terahertz (THz) spectrometer by combining THz photomultiplier tube (PMT) with metasurface and conventional Michelson interferometer. Because the THz-PMT response depends on incident electric-field strength following Fowler-Nordheim equation, we can directly obtain an electric field interferogram without any synchronized optical probe pulse in contrast to THz-time-domain-spectroscopy (THz-TDS). The DR of corresponding power...

Transition edge sensor microcalorimeters can be used in many optical quantum measurements because of its low dark counts, high efficiency, and resolving power a photon number weak light pulses. In order to increase count rates up few MHz, we have developed titanium transition for the measurements, performances were analysed. Titanium is one ideal superconductor higher temperature lower reflectance at 1.5 wavelength. Our film was fabricated with electron-beam evaporation, showed residual...

A continuously tunable, phase-locked, single-frequency, continuous-wave (cw) terahertz generator has been demonstrated around 120 GHz, corresponding to the spectral bandwidth of F-band unitraveling-carrier photodiode (UTC-PD) used as a photomixer in this study. This cw-terahertz is based on photomixing an accurately tunable cw laser and tightly fixed optical frequency region, phase locked two independent combs. The continuous tuning range presented method was three orders magnitude 0.1 THz 1...

A phase-locked 110-GHz continuously-tunable optical-single-frequency generator is developed based on a phase-stabilized fiber-based comb. Stability of the optical frequencies at 1s are 3.0 and 31×10–12 scanning speeds 0.17 1 GHz/s, respectively.

We constructed a system that can generate phase-controlled terahertz (THz) pulses using fan-out periodically poled lithium tantalate crystal and an optical pulse shaper containing spatial light modulator. The phase of each THz frequency components could be controlled by manipulating the delay time corresponding pulses. Using system, we generated arbitrarily group-velocity-dispersion-controlled pulses, where chirp parameter was 2.53 ps2/rad between 0.6 1.5 THz. In addition,...

Abstract A novel lightwave‐driven detector that combines photomultiplier tube (PMT) technology with structured metasurfaces is presented to enable efficient detection of long‐wavelength radiation in the mid‐infrared (mid‐IR) terahertz (THz) range. This overcomes limitations conventional PMT technology, which cannot efficiently detect wavelengths longer than 1.7 m. The approach utilizes radiation's instantaneous electric field facilitate field‐driven electron emission from metasurfaces,...

We demonstrate a method of measuring group refractive indices ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow class="MJX-TeXAtom-ORD"> <mml:msub> <mml:mi>n</mml:mi> <mml:mi mathvariant="normal">g</mml:mi> </mml:mrow> </mml:msub> </mml:math> ) by using only temporal waveform color-selective multi-pulse (CSMP) generated with spatial-light-modulator-based optical pulse shaper. Each the CSMP is characterized different spectral components. Thus, sample can...

Lightwave-Driven Long-Wavelength Photomultipliers In article number 2300417, Simon J. Lange and colleagues present a metasurface-based photomultiplier tube for long-wavelength lightwaves. The electric field of the incident lightwaves is concentrated onto highly sub-wavelength confinement volumes on metasurface, which enables electrons metasurface to emit into electron multiplication unit detection. can be tuned all infrared lightwave frequencies.

A THz detector with both high sensitivity and fast time response has been required for industrial applications such as nondestructive testing (NDT), security, spectroscopy. Through a collaboration the Technical University of Denmark (DTU), we have recently developed THz-sensitive point imager based on metasurface photomultiplier tube (PMT) image intensifier (I.I.) technologies, respectively. is one unique characteristics these devices: PMT-based provides nanosecond while I.I.- capable frame...

Coaxial time-resolved spectroscopy (TRS) based on a pump–probe technique using color-selective double pulse (CSDP) is proposed. The CSDP, generated an optical shaper (OPS), was composed of different spectral components. Coaxially propagating CSDPs were used for pump and weak probe pulses. As proof concept, we evaluated the transient absorption ZnTe crystal from difference between temporal waveforms output chirped with without OPS. Upon changing width pulse, measured reaction 0.2 ps, which...

We use an injection-seeded terahertz (THz)-wave Parametric Generator (is-TPG) source with a THz-PMT detector for spectroscopic measurements on water vapor concentration in air and doping levels of semiconductor wafers. The has highly non-linear response to changes the electric field strength from is-TPG source, which allows precise characterization miniscule absorption spectrum. perform frequency sweep 0.7 1.2 THz show that our signal drops significantly at lines. In addition, we measure...

Distance measurements using the 821st-harmonic of intermode beat frequency in an optical comb with optical-sub-wavelength accuracy are demonstrated. Direct comparison a laser interferometer for same setup reveals good agreement to 20-nm.

A continuously tunable, phase-locked, THz synthesizer has been demonstrated. This is based on photomixing of two optical frequency synthesizers composed CW laser and comb, its output the same uncertainty as that a microwave standard used.

We propose a new structure of TES and series connection radiation absorber, which can stabilize the absorber temperature through negative feedback process in absorber. consider that this self-heating might allow to improve detection efficiency with large effective area high count rate by cooling power inside The 150 mum times gold film 25 heat sensor made Iridium/Gold bi-layer superconductor has Tc 110 mK are biased series. In device generates self Joule heating certain extent maintain...

Arbitrary single-frequency CW-THz-wave generator based on two-independent femtosecond fiber-combs is presented. Continuous tuning of a 120-GHz CW wave was demonstrated across several MHz, which limited by electric bandwidth THz-spectrum analyzer for evaluation.

We present arbitrary single-frequency continuous-wave (CW) terahertz (THz) generator based on photomixing of a scanned CW laser and fixed laser, which are locked to two independent optical combs, respectively. Behavior tight locking continuous tuning its output frequency is monitored at real time by THz-comb-referenced spectrum analyzer.

目的 1) サンプルカードによるローラカードの伝達関数の決定.2) ローラカードを閉ループで制御する際の最適調整条件の検討.方法1) 系の骨格は過渡応答法によって推測し, その時定数はフィードローラの回転を周期的に停転することによって長方形波入力を作り, その出力の分散より求める.2) ウエブむらが定常不規則でガウシャンノイズとした時の制御装置の最適調整値を求める. 成果 ローラカードの伝達関数は, むだ時間をもつ1次比例系となった.2) ローラカードのように大きなむだ時間を持つ系にはPID制御がもっともよい.3) PD制御はP制御やPI制御よりむしろよい制御をする.