Open AccessEfficient excitations of radially and azimuthally polarized Nd^3+:YAG ceramic microchip laser by use of subwavelength multilayer concentric gratings composed of Nb_2O_5/SiO_2
Author(s) -
Jian-Lang Li,
Ken–ichi Ueda,
Lanxiang Zhong,
Mitsuru Musha,
Akira Shirakawa,
Takashi Sato
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.010841
Subject(s) - optics , materials science , laser , slope efficiency , grating , extinction ratio , polarization (electrochemistry) , diffraction efficiency , refractive index , laser beam quality , optoelectronics , fiber laser , laser beams , physics , wavelength , chemistry
Cylindrical vector beams were produced from laser diode end-pumped Nd:YAG ceramic microchip laser by use of two types of subwavelength multilayer gratings as the axisymmetric-polarization output couplers respectively. The grating mirrors are composed of high- and low-refractive- index (Nb(2)O(5)/SiO(2)) layers alternately while each layer is shaped into triangle and concentric corrugations. For radially polarized laser output, the beam power reached 610mW with a polarization extinction ratio (PER) of 61:1 and a slope efficiency of 68.2%; for azimuthally polarized laser output, the beam power reached 626mW with a PER of 58:1 and a slope efficiency of 47.6%. In both cases, the laser beams had near-diffraction limited quality. Small differences of beam power, PER and slope efficiency between radially and azimuthally polarized laser outputs were not critical, and could be minimized by further optimized adjustment to laser cavity and the reflectances of respective grating mirrors. The results manifested, by use of the photonic crystal gratings mirrors and end-pumped microchip laser configuration, CVBs can be generated efficiently with high modal symmetry and polarization purity.