Development and future prospects of terahertz technology

Hangyo, Masanori

doi:10.7567/jjap.54.120101

Cited by 148 publications

(66 citation statements)

References 132 publications

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“…Compact, high-power, and room-temperature terahertz (THz) sources are highly sought after to enable the practical realization of vast applications of THz waves [1][2][3][4][5], such as sensing and non-destructive imaging for safety and security [6][7][8][9][10], medical diagnosis [11][12][13], and ultrabroadband wireless communications [14][15][16]. Several types of THz light sources and/or oscillators (such as THz quantum cascade lasers [17][18][19][20][21][22], p-Ge lasers [23,24], and resonant tunneling diode (RTD) oscillators [25]) have been developed so far.…”

Section: Introductionmentioning

confidence: 99%

Terahertz light-emitting graphene-channel transistor toward single-mode lasing

et al. 2018

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Abstract:A distributed feedback dual-gate graphenechannel field-effect transistor (DFB-DG-GFET) was fabricated as a current-injection terahertz (THz) light-emitting laser transistor. We observed a broadband emission in a 1-7.6-THz range with a maximum radiation power of ~10 μW as well as a single-mode emission at 5.2 THz with a radiation power of ~0.1 μW both at 100 K when the carrier injection stays between the lower cutoff and upper cutoff threshold levels. The device also exhibited peculiar nonlinear threshold-like behavior with respect to the current-injection level. The LED-like broadband emission is interpreted as an amplified spontaneous THz emission being transcended to a single-mode lasing. Design constraints on waveguide structures for better THz photon field confinement with higher gain overlapping as well as DFB cavity structures with higher Q factors are also addressed towards intense, single-mode continuous wave THz lasing at room temperature.

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Section: Introductionmentioning

confidence: 99%

Terahertz light-emitting graphene-channel transistor toward single-mode lasing

et al. 2018

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“…[1][2][3] Compact and coherent solid-state sources are important components for these applications. Because the THz region is located between the light and millimeter waves, the THz sources are investigated with optical and electron devices.…”

Section: Introductionmentioning

confidence: 99%

Measurements of temperature characteristics and estimation of terahertz negative differential conductance in resonant-tunneling-diode oscillators

2017

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The temperature dependences of output power, oscillation frequency, and current-voltage curve are measured for resonant-tunneling-diode terahertz (THz) oscillators. The output power largely changes with temperature owing to the change in Ohmic loss. In contrast to the output power, the oscillation frequency and current-voltage curve are almost insensitive to temperature. The measured temperature dependence of output power is compared with the theoretical calculation including the negative differential conductance (NDC) as a fitting parameter assumed to be independent of temperature. Very good agreement was obtained between the measurement and calculation, and the NDC in the THz frequency region is estimated. The results show that the absolute values of NDC in the THz region significantly decrease relative to that at DC, and increases with increasing frequency in the measured frequency range.

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“…The THz band is ideal to study electrodynamic properties of materials from metals to insulators, since the frequency is lower than the typical plasma frequency of metals (about 10 15 Hz) that defines the frequency above which the metal becomes transparent to radiation. Coherent THz radiation can provide valuable information on the complete set of the complex electrodynamic parameters [34] (refractive index (ñ) permittivity (ε) and /or conductivity (σ) characterizing a material whatever it is an insulator or metallic like. The complex refractive index (ñ = n + i k) furnishes information on both the delay (n) and the absorption (k).…”

Section: Thz Spectroscopymentioning

confidence: 99%

THz Measurement Systems

Angrisani¹,

Cavallo²,

Liccardo³

et al. 2016

New Trends and Developments in Metrology

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The terahertz (THz) frequency region is often defined as the last unexplored area of the electromagnetic spectrum. Over the past few years, the full access has been the objective of intense research efforts. Progress in this area has played an important role in opening up the possibility of using THz electromagnetic radiation (T-waves) in science and in realworld applications. T-waves are not perceptible by the human eye, are not ionizing, and have the ability to cross many non-conducting materials such as paper, fabrics, wood, plastic, and organic tissues. Moreover, the use of THz radiation allows non-destructive analysis of the materials under investigation both by study of their "fingerprint" via spectroscopic measurements and by high-resolution spatial imaging operations, exploiting the see-through capability of T-waves. Such technology can be applied in diverse areas, spanning from biology to chemical, pharmaceutical, environmental sciences, etc. In this chapter, we will present the typical architecture of measurement systems based on the THz technology, detailing what are the parameters that define their performance, the measurement methods, and the related errors and uncertainty, and focusing at the end on the use of time-domain spectroscopy for the evaluation of different material properties in this specific frequency region.

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Development and future prospects of terahertz technology

Cited by 148 publications

References 132 publications

Terahertz light-emitting graphene-channel transistor toward single-mode lasing

Terahertz light-emitting graphene-channel transistor toward single-mode lasing

Measurements of temperature characteristics and estimation of terahertz negative differential conductance in resonant-tunneling-diode oscillators

THz Measurement Systems

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