Mode Conversion and Transfer of Orbital Angular Momentum Between Hermite-Gaussian and Laguerre-Gaussian Beams

Abstract

The cross phase (CP) opens up a new horizon for the generation and measurement of vortex beams, and the conversion between Hermite-Gaussian (HG) and Laguerre-Gaussian (LG) modes can be done with a CP. However, the conversion plane is in the far plane, and the width cannot be adjusted. In this article, we present a more convenient and practical mode converter between HG and LG modes based on CP combined with a lens. The feasibility of the converter for the conversion between two modes is theoretically analyzed. The conversion can be accomplished in the determined plane and the width of converted beam can be controlled by adjusting the parameter of converter. Proof-of-concept experiment is carried out to verify theoretical analysis and the experimental results are agree well with theoretical simulations. The transfer of orbital angular momentum (OAM) between two modes after passing through the converter is also analyzed. From the perspective of OAM conservation, the required parameter conditions for the converter are discussed. In principle, such a converter as proposed here might even be applied to microwave, millimeter wave, and terahertz OAM fields.

The Spatial Mapping of Interconversion Between Laguerre-Gaussian and Hermite-Gaussian Beams Array With an Astigmatism Phase

“…The experimental results of the interconversion between LG and HG beams with the astigmatism phase are well known [30], therefore, in this paper, the LG beams arrays with radial index p=0 are only generated to verify the above derived theories. A spatial light modulator (SLM) is usually used to generate the LG beams [31].…”

Deep Learning Recognition of Orbital Angular Momentum Modes Over Atmospheric Turbulence Channels Assisted by Vortex Phase Modulation

“…There are various types of beams that can carry OAM, such as Laguerre-Gaussian beams [37] and high-order Bessel-Gaussian beams [38]. Without loss of generality, in this paper, we use a simple vortex beam of which the optical field is given by…”

Rectangular Beam Pumped Raman Microchip Laser for Generating Multiwavelength High‐Order Hermite–Gaussian Lasers and Vortex Lasers

“…Various vortex beams carrying orbital angular momentum (OAM) have been obtained from HG 0,n mode lasers by using astigmatic mode converter. [12,13] The vortex lasers and petal-like lasers oscillating at versatile wavelengths converted with nonlinear frequency conversion [14,15] have broad room for application fields of optical capture [16] and quantum communication. [17] Generally, spatial light modulators (SLMs) are widely used to convert Gaussian beams into HG beams.…”