GUOPING LIN,* YAQIN CAO, RANRAN JI, CUIFANG HOU, AND ZEHUANG LU
MOE Key Laboratory of Fundamental Physical Quantities Measurement, Hubei Key Laboratory of Gravitation and Quantum Physics,
School of Physics, Huazhong University of Science and Technology, Wuhan 430074, China
*Corresponding author: guoping_lin@hust.edu.cn
Vortex laser beams carrying orbital angular momentum have been attracting a lot of interest in recent years. Here we demonstrate the direct generation of a vortex laser in a monolithic nonplanar ring cavity. The unidirectional and single-frequency operation of Laguerre–Gaussian modes is observed and characterized. Fork interferograms have been obtained using a simple interferometer based on a planoconcave lens, and the topological charge of vortex beam is determined. A spectral linewidth as narrow as 2.3 kHz is measured by beating with a reference laser. We believe that such a high coherent vortex laser can be beneficial for numerous applications, including precision measurements and optical communications. © 2018 Optical Society of America
https://doi.org/10.1364/OL.43.004164
