Measurement of the wavelength dependence of the threshold of laser-induced gas breakdown

Measurements of the threshold intensity for breakdown over the wavelength range 720-840 nm have been made at atmospheric pressure in several gases, by means of a high output power laser pumped, tunable dye laser. Although it may be expected that the resonant phenomena observed in earlier experiments would be more pronounced at lower pressures, the authors have found that over the entire wavelength range studied, the results showed the direct dependence on both wavelength and pulse duration predicted by cascade theory.