Creation of Laguerre-Gaussian laser modes using diffractive optics

Abstract

Diffractive optics are used to create low- and high-order Laguerre-Gaussian (LG) beams from the output of a diode laser. We examine the mode purities, conversion efficiencies, extinction ratios, and propagation characteristics. We present detailed analyses of the beam profiles for one low-order $({\mathrm{LG}}_{0}^{1})$ and one high-order $({\mathrm{LG}}_{1}^{2})$ Laguerre-Gaussian mode. Modeling the ${\mathrm{LG}}_{1}^{2}$ beam as a superposition of LG modes, we find $(99.3\ifmmode\pm\else\textpm\fi{}0.9%)$ of the laser intensity in the ${\mathrm{LG}}_{1}^{2}$ mode, a mode purity greater than for LG beams created by other methods external to the laser cavity. The high mode purity may be useful in making atom traps for precision measurements and for Bose-Einstein condensation.