Broadband and narrowband laser-based terahertz source and its application for resonant and non-resonant excitation of antiferromagnetic modes in NiO.

A V Ovchinnikov,C P Hauri,O V Chefonov,M B Agranat

doi:10.1364/oe.27.027273

A V Ovchinnikov, C P Hauri + Show 2 more

Open Access

https://doi.org/10.1364/oe.27.027273

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Journal: Optics express	Publication Date: Sep 13, 2019
Citations: 17	License type: cc-by

Affiliation: Joint Institute for High Temperatures

Abstract

A versatile table-top high-intense source of terahertz radiation, enabling to generate pulses of both broadband and narrowband spectra with a tunable frequency up to 3 THz is presented. The terahertz radiation pulses are generated by optical rectification of femtosecond pulses of Cr:forsterite laser setup in nonlinear organic crystal OH1. Electric field strengths of broadband and narrowband terahertz pulses were achieved close to 20 MV/cm and more than 2 MV/cm, correspondingly. Experiments on excitation of spin subsystem oscillations of an antiferromagnetic NiO were carried out. Selective excitation of 0.42 THz mode was observed for the first time at room temperature by a narrowband terahertz pulses tuned close to mode frequency.

Highlights

In recent years, sources of single-cycle and multi-cycle pulses of terahertz (THz) radiation have been increasingly used for both fundamental and applied research
Single-cycle THz pulses are generated in table-top setup by optical rectification of femtosecond laser pulses in nonlinear organic [1,9] and inorganic [10,11] crystals, in gas-plasma driven by two-colour laser [12], and in large scale accelerator facilities using relativistic charged particle beams [3]
In recent works, [1,9] it was shown that the method of optical rectification of femtosecond laser pulses with a wavelength of 1240 nm allows to generate linearly polarized THz pulses in various nonlinear organic crystals (DAST, DSTMS, OH1) with high pulse energy and conversion efficiency

Summary

Introduction

Sources of single-cycle and multi-cycle pulses of terahertz (THz) radiation have been increasingly used for both fundamental and applied research. Single-cycle THz pulses are generated in table-top setup by optical rectification of femtosecond laser pulses in nonlinear organic [1,9] and inorganic [10,11] crystals, in gas-plasma driven by two-colour laser [12], and in large scale accelerator facilities using relativistic charged particle beams [3]. Despite the numerous of studies in the field of generation of intense terahertz pulses, nowadays there is no versatile THz source with high conversion efficiency and providing both broadband and narrowband THz generation with a tunable central frequency. In this paper we present a versatile table-top laser-based easy-to-implement THz source that allows to generate both broadband and narrowband pulses with tunable center frequency with high energy. The resonant and non-resonant effects of THz radiation pulses of our source on the spin subsystem of a typical NiO antiferromagnetic at room temperature are demonstrated

Versatile broadband and narrowband laser-based THz source

Excitation of spin subsystem oscillations of an antiferromagnetic NiO

Findings

Conclusion