Ultra-low variable repetition rate Nd:YVO4 laser mode-locked with semiconductor saturable absorber mirrors

Here, we report on a table-top long-cavity (up to 100 m) medium power laser capable of producing 13-ps pulses at three different ultra-low repetition rates of 4.1 MHz, 2.6 MHz and 1.5 MHz. The latter is to our knowledge, the lowest repetition rate ever reported for a mode-locked solid state laser, without cavity dumping. The average power was 4.1 W, 3.9 W and 3.5 W respectively. A wedged cylindrical crystal of Nd:YVO₄ (1% Nd) was dual-end pumped with a fiber coupled laser diode module of nominal power 18 W and center wavelength ∼805 nm. The laser was mode-locked with InGaAs quantum well semiconductor saturable absorber mirror(s) (SESAM) grown by metal-organic chemical vapor deposition technique.