High repetition rate 880 nm diode-directly-pumped electro-optic Q-switched Nd:GdVO4 laser with a double-crystal RTP electro-optic modulator

By using a double-crystal RbTiOPO4 (RTP) electro-optic (EO) modulator, we present a high repetition rate 880 nm diode-directly-pumped EO Q-switched adhesive-free bond (AFB) composite Nd:GdVO4 laser for the first time. The stable working range extends from 10 to 280 kHz; at the highest repetition rate of 280 kHz, the maximum average output power of 11.2 W and the shortest pulse width of 18.4 ns are achieved at an absorbed pump power of 19.3 W, corresponding to an optical-optical conversion efficiency of 58% and a slope efficiency of 62.2%. A near-diffraction-limit beam is obtained with beam quality factor of M-2 approximate to 1.2 at the maximum absorbed pump power. Because of the weak thermal effect, the M-2 factor almost remains constant at different pulse repetition rates. (C) 2013 Elsevier B.V. All rights reserved.