Dispersive temporal compression of laser pulses as an alternative solution to the self focusing problem in laser amplifier chains

In response to the discovery of a nonlinear index of refraction (n/sub 2/ ) in Nd: glass laser media, experimenters have traditionally expanded the beam diameter (and reduced the intensity) to alleviate the self-focusing tendency. It is proposed here to reduce the peak intensity by injecting a lower intensity and longer-duration pulse into the amplifier chain. It is predicted that the glass nonlinearity will impress upon the pulse a chirp suitable for efficient temporal compression. This may result in more efficient laser operation. Related schemes have been used in radar systems. As an example, the evolution of a 1 nsec (full 1/e duration) temporally Gaussian pulse in a 2 m long Nd: glass laser chain was calculated. For a chain averaged intensity of 2 GW/cm/sup 2/, one calculates that the pulse could be subsequently compressed (by a series of GiresTournois interferometers) to 125 psec with good stability against input pulse amplitude noise. (auth