Abstract-Development of intense terahertz light source for forming periodic structures on material surface

                                    

Chikai Hosokawa, Masaki Hashida, Takeshi Nagashima,  Shunsuke Inoue, Shuji Sakabe,

 https://onlinelibrary.wiley.com/doi/abs/10.1002/ecj.12284

We have developed an intense terahertz wave source aiming at in situ measurement of periodic surface structures induced by terahertz waves on solid materials with high‐spatiotemporal resolution. An intense terahertz wave of 119 µJ was generated from a Lithium Niobate crystal induced with an intense laser with fluence of 25 mJ/cm2 by tilted pulse front method. By applying a negative chirp to the laser pulse, the pulse width spread inside the crystal was compensated, and the output of the terahertz wave was maximized.

Abstract-Terahertz Radiation from Combined Metallic Slit Arrays

Dazhi Li, Makoto Nakajima, Masahiko Tani, Jinfeng Yang, Hideaki Kitahara, Masaki Hashida, Makoto Asakawa, Wenxin Liu, Yanyu Wei,  Ziqiang Yang,

https://www.nature.com/articles/s41598-019-43072-2

We report an approach to efficiently generate terahertz radiation from a combined periodic structure. The proposed configuration is composed of two metallic slit arrays deliberately designed with different periodic length, slit width and depth. We found that the combination of the two slit arrays could provide special electromagnetic modes, which exhibit nonradiative property above the surface of one slit array and radiative property inside the other one. An electron beam holding proper energy could resonate with those modes to generate strong and directional electromagnetic radiations in the terahertz regime, indicating that the approach has the potential in developing high-performance terahertz radiation sources.

Abstract-Half-cycle terahertz surface waves with MV/cm field strengths generated on metal wires

Kensuke Teramoto, Shigeki Tokita, Tokinori Terao, Shunsuke Inoue,  Ryo Yasuhara,  Takeshi Nagashima, Sadaoki Kojima, Junji Kawanaka,  Kazuaki Mori ,Masaki Hashida, Shuji Sakabe,

Schematic of the experimental setup for electro-optical measurement of a THz surface wave. The observation point is located 100 mm from the laser focal point at radial distance r (mm) from the wire center.

https://aip.scitation.org/doi/abs/10.1063/1.5031873


Irradiating a metal wire with an intense femtosecond laser pulse induces a terahertz (THz) surface wave that travels along the wire. Here, the characteristics of the THz surface wave generated by the laser–wire interaction are investigated in detail by using an electro-optical method to determine the dependence of surface wave properties on laser energy and wire diameter. The surface wave is distributed by the Hankel function in the wire radial direction. On the wire surface, the electric field is estimated to be MV/cm. The peak electric field of the surface wave and the conversion efficiency from laser energy to surface wave energy are found to be proportional to the laser energy raised to the power of 0.67 and 0.3, respectively.

Abstract-Induction of subterahertz surface waves on a metal wire by intense laser interaction with a foil

Kensuke Teramoto, Shunsuke Inoue, Shigeki Tokita, Ryo Yasuhara, Yoshihide Nakamiya, Takeshi Nagashima, Kazuaki Mori, Masaki Hashida, and Shuji Sakabe

https://journals.aps.org/pre/abstract/10.1103/PhysRevE.97.023204

We have demonstrated that a pulsed electromagnetic wave (Sommerfeld wave) of subterahertz frequency and 11-MV/m field strength can be induced on a metal wire by the interaction of an intense femtosecond laser pule with an adjacent metal foil at a laser intensity of $8.5\times {10}^{18}W/c{m}^2$. The polarity of the electric field of this surface wave is opposite to that obtained by the direct interaction of the laser with the wire. Numerical simulations suggest that an electromagnetic wave associated with electron emission from the foil induces the surface wave. A tungsten wire is placed normal to an aluminum foil with a gap so that the wire is not irradiated and damaged by the laser pulse, thus making it possible to generate surface waves on the wire repeatedly.

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Abstract-Induction of sub-terahertz surface wave on a metal-wire by intense laser interaction with a foil

Kensuke Teramoto, Shunsuke Inoue, Shigeki Tokita, Ryo Yasuhara, Yoshihide Nakamiya, Takeshi Nagashima, Kazuaki Mori, Masaki Hashida, and Shuji Sakabe

https://journals.aps.org/pre/accepted/d4074Y14Qd812c64160d2058a2d69614bb667cd2d

We have demonstrated that a pulsed electromagnetic wave (Sommerfeld wave) of sub-terahertz frequency and 11-MV/m field strength can be induced on a metal wire by the interaction of an intense femtosecond laser pule with an adjacent metal foil at a laser intensity of 8.5\texttimes 10\mathrm{18\thinspace }W/cm2. The polarity of the electric field of this surface wave is opposite to that obtained by the direct interaction of the laser with the wire. Numerical simulations suggest that an electromagnetic wave associated with electron emission from the foil induces the surface wave. A tungsten wire is placed normal to an aluminum foil with a gap so that the wire is not irradiated and damaged by the laser pulse, thus making it possible to generate surface waves on the wire repeatedly.

Abstract:Intense terahertz emission from atomic cluster plasma produced by intense femtosecond laser pulses

Image by mightyohm via Flickr

http://apl.aip.org/resource/1/applab/v99/i26/p261503_s1?isAuthorized=no

Terahertz (THz) emission from argon cluster plasma, generated by intense femtosecond laser pulses in the energy range of 10–70 mJ, has been investigated. THz polarization, energy dependence, and angular distribution were measured to provide an initial discussion on the mechanisms of THz emission. THz pulses of much higher energy were generated from argon clusters than from argon gas, which indicates that plasma produced from atomic clusters holds considerable promise as an intense THz source.

© 2011 American Institute of Physics