  An AOQ (acoustic-optic Q-switched) laser with cavityless weak-feedback
configuration is demonstrated based on a Nd:GdVO4 bounce geometry. The laser
can operate at a repetition up to 500 kHz with the output power above 4W. The
pulse-width at 100 kHz reaches 5.2 ns, which is 4.3 times the round-trip time.
A theory of Q-switched cavityless weak-feedback laser is proposed for the first
time, to our best knowledge. This theory is very suitable for analyzing short
pulses comparable to round-trip time. By utilizing the theory, simulation is
implemented for our experimental conditions. The consistence between the
simulation and the experimental results proves the validity of our theory.
