Magnetic field and temperature dependence of terahertz radiation from InAs surfaces excited by femtosecond laser pulses

Hangyo, Masanori; Migita, M.; Nakayama, Kazunori

doi:10.1063/1.1399023

Cited by 22 publications

(12 citation statements)

References 18 publications

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“…[65] Singh et al have reported THz generation by mixing two cosh-Gaussian laser beams in a density rippled plasma. We consider the maximum magnetic field strength to be 60 kGauss (kG) or 6 Tesla (T), but there are some experimental references that use magnetic fields from 5 up to 10 T. [74][75][76] In our scheme, the CO 2 laser pulse [37,39] can provide desired frequencies for incident laser beams. [67] Hematizadeh et al have presented a scheme for THz generation based on the nonlinear mixing of two oblique incident laser beams on an over-dense magnetized plasma; they have also reported generation of THz radiation from under-dense plasma by taking advantage of right-hand circularly polarized (RCP) and left-hand circularly polarized (LCP) waves via different laser beam profiles.…”

Section: Introductionmentioning

confidence: 99%

Generation of terahertz radiation via cosh‐Gaussian and top‐hat laser beams in a collisional magnetized plasma

Hematizadeh

Jazayeri

Ghafary

2018

Contributions to Plasma Physics

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This paper presents a scheme to generate terahertz (THz) radiation by the beating of lasers in a rippled density collisional magnetized plasma. The laser beams exert a ponderomotive force on the electrons of plasma and impart them with oscillatory velocity at the different frequencies of lasers. The direction of the uniform static magnetic field makes an angle with respect to the propagation direction of laser beams; in this case, two-mode waves can propagate in plasma. We derive the general formulas for efficiency and THz field amplitude with arbitrary laser beam profiles. The efficiency of the emitted radiations is found to be sensitive to laser profiles, the angle between laser beams and static magnetic field, collision frequency, and magnetic field strength. A comparison between the generated THz radiation by top-hat and cosh-Gaussian laser beams reveals, at the same conditions, that the generated THz radiation by top-hat laser beams produces a stronger ponderomotive force and a higher efficiency. KEYWORDScosh-Gaussian beam, terahertz generation, top-hat beam, uniform magnetic field 1

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Section: Introductionmentioning

confidence: 99%

Generation of terahertz radiation via cosh‐Gaussian and top‐hat laser beams in a collisional magnetized plasma

Hematizadeh

Jazayeri

Ghafary

2018

Contributions to Plasma Physics

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“…In order to obtain intense THz emission, earlier works focused on searching a proper compound semiconductor and subsequently adjusted the doping concentration [3][4][5]. Moreover, external magnetic fields, which are of the order of 1 T, were used for enhancing the THz emission [6][7][8][9][10][11] ; however, the THz spectroscopic system with the use of the magnetic field generator lacks the advantage of being convenient.…”

Section: Introductionmentioning

confidence: 99%

Intense emission of terahertz electromagnetic wave from an undoped GaAs/n ‐type GaAs epitaxial layer structure

Takeuchi

Yanagisawa

Hasegawa

et al. 2009

Phys. Status Solidi (c)

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We have investigated the emission of the terahertz (THz) electromagnetic wave from an undoped GaAs (200 nm)/n ‐type GaAs (3 μm) epitaxial layer structure (i ‐GaAs/n ‐GaAs structure), where the doping concentration of the n ‐GaAs layer is 3 × 1018cm‐3. It is found that the first‐burst amplitude of THz wave of the i ‐GaAs/n ‐GaAs structure is considerably stronger than that of an n ‐GaAs crystal, which means that the i ‐GaAs layer enhances the THz emission intensity. The first‐burst amplitude of the i ‐GaAs/n ‐GaAs structure, by tuning the pump‐beam energy to the higher energy side, exceeds that of an i ‐InAs crystal known as one of the most intense THz emitters. We, therefore, conclude that the i ‐GaAs/n ‐GaAs structure is useful to obtain intense THz emission. From the pump‐beam energy dependence of the first‐burst amplitude, the THz‐emission mechanism of the i ‐GaAs/n ‐GaAs structure is attributed to the surge current of the photogenerated carriers flowing through the i ‐GaAs layer. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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“…However, a large number of reports on studies with pulse excitation of semiconductor structures, mostly single or few THz cycles, exists. In most of these investigations, the goal was not the efficient generation of THz radiation, but rather the study of the dynamics of photogenerated carriers in surface depletion layers, 48,49 in semiconductor superlattices, 126 or large electric fields in p-i-n diodes. 120 Therefore, no attempts were made to calibrate the observed signals.…”

Section: -29mentioning

confidence: 99%

“…This induces a surface-parallel component of near-surface carrier transport due to the Lorentz force. [48][49][50] A simpler way to generate strong in-plane components of the carrier acceleration and, hence, strong in-plane components of the THz fields, is with the application of a DC bias to large area coplanar metallic contacts. This creates a strong in-plane electric field.…”

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confidence: 99%

Tunable, continuous-wave Terahertz photomixer sources and applications

Preu

Döhler

Malzer

et al. 2011

Journal of Applied Physics

432

293

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Realization of gigahertz-frequency impedance matching circuits for nano-scale devices Appl. Phys. Lett. 101, 053108 (2012) Synchronization of a renewable energy inverter with the grid J. Renewable Sustainable Energy 4, 043103 (2012) Monolithic high-temperature superconducting heterodyne Josephson frequency down-converter Appl. Phys. Lett. 100, 262604 (2012) Generation of pure phase and amplitude-modulated signals at microwave frequencies Rev. Sci. Instrum. 83, 064705 (2012) Additional information on J. Appl. Phys. This review is focused on the latest developments in continuous-wave (CW) photomixing for Terahertz (THz) generation. The first part of the paper explains the limiting factors for operation at high frequencies $ 1 THz, namely transit time or lifetime roll-off, antenna (R)-device (C) RC rolloff, current screening and blocking, and heat dissipation. We will present various realizations of both photoconductive and p-i-n diode-based photomixers to overcome these limitations, including perspectives on novel materials for high-power photomixers operating at telecom wavelengths (1550 nm). In addition to the classical approach of feeding current originating from a small semiconductor photomixer device to an antenna (antenna-based emitter, AE), an antennaless approach in which the active area itself radiates (large area emitter, LAE) is discussed in detail. Although we focus on CW photomixing, we briefly discuss recent results for LAEs under pulsed conditions. Record power levels of 1.5 mW average power and conversion efficiencies as high as 2 Â 10 À3 have been reached, about 2 orders of magnitude higher than those obtained with CW antenna-based emitters. The second part of the paper is devoted to applications for CW photomixers. We begin with a discussion of the development of novel THz optics. Special attention is paid to experiments exploiting the long coherence length of CW photomixers for coherent emission and detection of THz arrays. The long coherence length comes with an unprecedented narrow linewidth. This is of particular interest for spectroscopic applications, the field in which THz research has perhaps the highest impact. We point out that CW spectroscopy systems may potentially be more compact, cheaper, and more accurate than conventional pulsed systems. These features are attributed to telecom-wavelength compatibility, to excellent frequency resolution, and to their huge spectral density. The paper concludes with prototype experiments of THz wireless LAN applications. For future telecommunication systems, the limited bandwidth of photodiodes is inadequate for further upshifting carrier frequencies. This, however, will soon be required for increased data throughput. The implementation of telecom-wavelength compatible photomixing diodes for down-conversion of an optical carrier signal to a (sub-)THz RF signal will be required.

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Magnetic field and temperature dependence of terahertz radiation from InAs surfaces excited by femtosecond laser pulses

Cited by 22 publications

References 18 publications

Generation of terahertz radiation via cosh‐Gaussian and top‐hat laser beams in a collisional magnetized plasma

Generation of terahertz radiation via cosh‐Gaussian and top‐hat laser beams in a collisional magnetized plasma

Intense emission of terahertz electromagnetic wave from an undoped GaAs/n ‐type GaAs epitaxial layer structure

Tunable, continuous-wave Terahertz photomixer sources and applications

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