Spontaneous generation of orbital angular momentum crystals using a monolithic Nd:YAG nonplanar ring laser

Guoping Lin,1,* Yaqin Cao,1 Zehuang Lu,1 and Yanne K. Chembo,2

1. MOE Key Laboratory of Fundamental Physical Quantities Measurement, Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

2. Georgia Tech—CNRS Joint International Laboratory [UMI 2958], Atlanta Mirror Site, School of Electrical and Computer Engineering, 777 Atlantic Dr. NW, Atlanta, Georgia 30332, USA

Abstract: We report the emission of localized orbital angular momentum (OAM) crystals in a millimeter-size monolithic Nd:YAG nonplanar ring laser. Narrow-linewidth single-frequency lasing in the kilohertz level featuring crystal-like vortices is obtained via phase locking of Laguerre-Gaussian modes in the cavity. It is found that the spatially degenerate OAM of high-order LG modes can be easily broken by superimposing a low-order mode, leading to crystal-like vortices. Our theoretical analysis is found to be in agreement with the experimental results for both intensity and interference patterns.

Opt. Lett. 44(2), 203--206 (2019)

https://doi.org/10.1364/OL.44.000203