Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group
  • 2019 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference
  • OSA Technical Digest (Optica Publishing Group, 2019),
  • paper cd_1_1

Comparative Study of Harmonic Generation in Air and Argon in Light Filaments Driven by Circularly Polarized mid-IR Pulses

Not Accessible

Your library or personal account may give you access

Abstract

A generation of optical harmonics by circularly polarized light, which is in general forbidden in an isotropic medium, was recently observed in molecular gases where molecules were aligned and oriented by another linearly polarized laser pulse [1] or by pulses with twisted polarization [2]. In order to generate nth-harmonic with circularly polarized light, a molecule has to “absorb” n photons, having the same handedness, and to emit a single nth harmonic photon while fulfilling the energy and the momentum conservation laws, meaning a necessity to excite the molecule to appropriate rotational state. One can do this by means of intrapulse rotational Raman scattering, which prepares the molecule in the excited state through a subsequent absorption of (n-1) same-handed photons [1]. All previously reported experimental studies on circular harmonic generation in molecular gases were performed with visible/near-IR drivers, in either gas jets or in standing cells and with pre-alignment of molecules by an additional laser pulses. Here we report on the studies of self-action of elliptically polarized mid-IR pulses on the generation of low-order harmonics in filaments ignited in air and in argon, representing a molecular and an atomic gas respectively. The harmonics were driven by 20-mJ, sub-100 fs mid-IR pulses, centred at 3.9 μm wavelength. In the experiments filamentation was assisted by focusing light with a spherical mirror of ROC=-2500 mm into an open-end tube, through which Ar gas was flown at slight overpressure. Polarization of the pulses was controlled by a broadband quarter wave plate (QWP). Spectra of 5th and 7th harmonics were recorded after the filaments with a grating spectrometer (HR4000, OceanOptics). Polarization state of the generated harmonics was analysed with a Glan-Taylor polarizer.

© 2019 IEEE

PDF Article
More Like This
Impact of Polarization on Mid-IR Air Filaments

V. Shumakova, C. Gollner, A. Baltuška, V. Yu. Fedorov, S. Tzortzakis, A. Voronin, A.V. Mitrofanov, A.M. Zheltikov, D. Kartashov, and A. Pugžlys
FM1Q.2 CLEO: QELS_Fundamental Science (CLEO:FS) 2018

Enhanced supercontinuum generation by polarization control of filamentation in molecular gases

Shermineh Rostami, Michael Chini, Khan Lim, Magali Durand, Matthieu Baudelet, Martin Richardson, Jean-Claude Diels, and Ladan Arissian
SF2D.5 CLEO: Science and Innovations (CLEO:S&I) 2015

Low-Order Harmonic Generation in Mid-Infrared Laser Filaments in Gases

Claudia Gollner, Valentina Shumakova, Audrius Pugzlys, Andrius Baltuska, and Pavel Polynkin
FF1C.2 CLEO: QELS_Fundamental Science (CLEO:FS) 2019

Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved