RUBY  LASERS

The very first laser discovered (by Theodore Maiman in 1960), the ruby laser is a three-level system having a high pumping threshold and requiring high pump energies. With the development of more efficient lasers, many of which are capable of CW operation, the demand for ruby lasers has diminished steadily, but it is still a useful source of intense pulsed red light for applications such as holography. The ability to Q-switch this laser results in fast, intense pulses of red light that cannot be generated by other means. Being confined somewhat to a narrow application market, many modern ruby lasers utilize EO Q-switches and often use a MOPA configuration in which pulses generated via a Q-switched oscillator are amplified by a separate rod outside the cavity of the oscillator laser. Energies of 1 J per pulse with a pulse length of 10 ns are common from a Q-switched ruby laser.