Eur. Phys. J. Plus (2022) 137: 623
https://doi.org/10.1140/epjp/s13360-022-02842-0

Regular Article

A study of grating diffraction and photon–phonon scattering in Raman–Nath diffraction

¹ Fujian Provincial Key Laboratory of Quantum Manipulation and New Energy Materials, College of Physics and Energy, Fujian Normal University, 350117, Fuzhou, China
² Fujian Provincial Collaborative Innovation Center for Advanced High-Field Superconducting Materials and Engineering, 350117, Fuzhou, China

^a ccweng@fjnu.edu.cn

Received: 17 March 2022
Accepted: 17 May 2022
Published online: 25 May 2022

Abstract

In this paper, the correlation between grating diffraction and photon–phonon scattering in Raman–Nath diffraction is investigated. A Raman–Nath diffraction model—the grating diffraction and photon–phonon scattering occur simultaneously and independently—is proposed. In the model, light is diffracted into multiple diffracted orders by the grating and any order diffracted light may be scattered into other diffracted orders by the photon–phonon scattering. Consequently, each order of diffracted light is composed of light waves frequency-shifted by different integer multiples of the ultrasonic frequency, resulting in the fact that its intensity signal consists of cosine signals whose frequencies are different integer multiples of the ultrasonic frequency. To confirm the model, the zeroth-order diffracted light in Raman–Nath diffraction are studied theoretical and experimentally. By Fourier transform, the spectrum of the zeroth-order diffracted light intensity signal is obtained. The spectrum shows that the intensity signal consists of cosine signals whose frequencies are different integer multiples of the ultrasonic frequency. Therefore, it is confirmed that the zeroth-order diffracted light is composed of light waves frequency-shifted by different integer multiples of the ultrasonic frequency. The theoretical and experimental results are in good agreement with the Raman–Nath diffraction model.