Modulation of two-color laser-induced filament terahertz emission by effective length variation

P.A Chizhov,A.A Ushakov,S.V Garnov,V.V Bukin,A.A Silaev

doi:10.1051/epjconf/201819503003

Abstract

Modulation of two-color laser-induced filament terahertz emission by effective length variation

Highlights

We show strong influence of phase matching between harmonics on overall THz power output and demonstrate that screening of a part of THz emission allows increasing the output power up to 20% of that for undisturbed emission
We demonstrate the possibility of spectral modulation by means of π-retarder screens for a distinct THz frequency
The SHG and plates are mounted on a moving table to change air path of two-color pulse before the filament and so the initial phase difference between harmonics

Summary

Introduction

We show strong influence of phase matching between harmonics on overall THz power output and demonstrate that screening of a part of THz emission allows increasing the output power up to 20% of that for undisturbed emission. A lens ( 25.4 mm, 1000 mm focal length) focuses laser radiation to create a filament in ambient air. A BBO crystal (SHG, 10x10x0.2 mm[3], I-type) converting part of radiation into second harmonic is placed on the optical pump path before the plasma.

Results

Conclusion