Generation of 15 nJ pulses from a highly efficient, low-cost multipass-cavity Cr3+:LiCAF laser

We describe the generation of enhanced pulse energies using a multipass-cavity (MPC) Cr(3)+:LiCAF laser, pumped by inexpensive, single spatial mode laser diodes. A semiconductor saturable absorber was used for stable mode-locked operation. The MPC reduced the pulse repetition rate to the approximately 10 MHz level, scaling pulse energies and intensities. With only 540 mW of absorbed pump power, 98 fs pulses with energies of 9.9 nJ and peak powers of approximately 101 kW, corresponding to 95 mW of average power at a repetition rate of 9.58 MHz, were generated. By increasing the intracavity negative dispersion, 310 fs pulses with energies of 15.2 nJ and peak powers of approximately 49 kW, corresponding to 160 mW of average power at 10.51 MHz repletion rate, were also generated. These results demonstrate that low-cost MPC Cr(3+)-doped colquiriite lasers can generate pulse energies and intensities comparable to more expensive Ti:sapphire lasers.