Overview on Second and Third Order Optical Nonlinear Processes
  To add the detailed information to the existed knowledge of nonlinear optics field, the nonlinear optical processes of the second and third order have been discussed in their respective susceptibility tensors in the presence of degenerate and non-degenerate optical wave frequencies mixing. This article reports on the all possible ways of wave mixing in the nonlinear interaction of waves in the presence of the medium. The advantage of high peak power pico- and femto-second laser pulses allow us to tune the wavelength of laser beams from UV to infrared region of the electromagnetic spectrum by different harmonic generations. These harmonic generations are described in all aspects and how their efficiency will be affected by other nonlinear processes, those cannot be removed by phase matching condition. The susceptibility terms involved in each nonlinear process are significantly discussed. Also, the probability of occurrence of each nonlinear process is comparatively studied over second and third nonlinear wave mixings. 
A Srinivasa Rao
physics.optics