Generation of high-order Laguerre-Gaussian modes in a Nd:YAG microchip laser by manipulating gain distribution

High beam quality lasers in form of high-order Laguerre-Gaussian with azimuthal index of n (LG0,n) have been widely used in optical communication, microparticle manipulation, condensate physics, laser beams self-focusing in plasma. To achieve these applications, compact solid-state lasers oscillating in LG0,n modes are crucial. Here, high-order LG0,n lasers are generated directly in a Nd:YAG microchip laser by manipulating gain distribution using a single-emitter laser-diode (LD) as pump source. The order of LG0,n lasers is tuned from 5 to 9 by adjusting the distance between Nd:YAG crystal and focus spot of y-axis of single-emitter LD (Δz). At Δz = 1.42 mm, the order of LG0,n lasers increases from 4 to 12 as input pump power increases. With beam quality factors (M2) nearing the theoretical value, high beam quality was achieved for LG0,n lasers. For the LG0,12 laser, with input pump power of 4.95 W, the output power is 448 mW and the optical conversion efficiency is 9%. High beam quality compact Nd:YAG microchip laser for generating high-order LG0,n modes provides compact laser sources for optical manipulation, quantum information processing and development of portable instruments. •High-order LG0,n modes have been generated in a Nd:YAG microchip laser pumped with a single-emitter laser diode.•Effects of pump power distribution of single-emitter laser diode on generation of LG0,n mode have been investigated.•Gain distribution for LG0,n mode oscillation was manipulated by adjusting waists and separation between fast- and slow-axis of laser diode.•Compact high-order LG0,n microchip laser has potential for optical manipulation, optical communications.