Strong sub-terahertz surface waves generated on a metal wire by high-intensity laser pulses.

Shigeki Tokita,Takeshi Nagashima,Masaki Hashida,Shuji Sakabe,Shunsuke Inoue

doi:10.1038/srep08268

Abstract

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip. This is particularly useful for applications that require high-field pulses. However, the generation of strong terahertz surface waves on a wire waveguide remains a challenge. Here, ultrafast field propagation along a metal wire driven by a femtosecond laser pulse with an intensity of 1018 W/cm2 is characterized by femtosecond electron deflectometry. From experimental and numerical results, we conclude that the field propagating at the speed of light is a half-cycle transverse-magnetic surface wave excited on the wire and a considerable portion of the kinetic energy of laser-produced fast electrons can be transferred to the sub-surface wave. The peak electric field strength of the surface wave and the pulse duration are estimated to be 200 MV/m and 7 ps, respectively.

Highlights

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip
We have reported the observation of a strong surface wave produced by relativistic laser interaction with a metal wire
We have demonstrated that femtosecond electron deflectometry using laseraccelerated electrons can be used as a powerful method for time- and space-resolved quantitative measurement of ultrafast electromagnetic dynamics induced by laser-plasma interactions in the relativistic intensity regime

Summary

Introduction

Terahertz pulses trapped as surface waves on a wire waveguide can be flexibly transmitted and focused to sub-wavelength dimensions by using, for example, a tapered tip This is useful for applications that require high-field pulses. Terahertz pulses trapped as surface waves (surface plasmon polaritons) on a metal wire can be flexibly transmitted[12] and focused to sub-wavelength dimensions by techniques such as using a tapered tip[13,14]. Numerical simulations indicate that a sub-terahertz transverse-magnetic (TM) surface wave was efficiently excited by laser-plasma interaction in the metal wire targets

Methods

Results

Conclusion