Harmonic generation in gases has been investigated by mixing of fundam
ental (1064nm) and second harmonic (532nm) of a 100-mJ 35-ps Nd:YAG la
ser. Even and odd harmonics of fundamental wavelength are generated by
wave-mixing, We have investigated in detail harmonic spectrum in Ar a
nd N-2, up to the 14(th) harmonics, versus the gas pressure and laser
intensity.