Giant pulse generation

A quantitative description of giant pulse generation is again given by a set of rate equations in the simplest case one for the inversion, another for the population density mo of the dye in the ground state So and a third for the laser light intensity nc. If excited state absorption has to be taken into account, additional rate equations would have to be added as described above in the section on nonlinear absorption. 

The output from a ruby giant-pulse laser (2 Joule, 30 nsec half-width, = 6943A) passes a KH2PO4 crystal where, due to the nonlinear characteristics of this material, the second harmonic at X = 3471 A is generated with an efficiency of 3 %.The two wavelengths are separated by means of a water filled quartz prism. The ultraviolet light pulse serves as pump pulse. 

Because of the relatively large dispersion from the electrons compared with the almost constant refractivity of the neutrals and the negligible contribution of the ions, it is possible, with simultaneous measurements at two different wavelength, to determine independent values of the density of electrons and of the nonelectronic components in the plasma 274). Alcock and Ramsden 275) used the light from a giant-pulse ruby laser and its second harmonic generated in an ADP-crystal (ammonium dihydrogen phosphate) to probe a pulsed plasma and its time-dependent density in a Mach-Zehnder interferometer. 

For a long time, as long as only one (giant-pulse) laser was used for excitation, the stimulated Raman effect [74] generated only the lines with the highest peak-scattering... 

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