The imaging theory of Raman induced Kerr effect spectroscopy (RIKES) in nonlinear confocal microscopy is presented in this paper. Three-dimensional point spread function (3D-PSF) of RIKES nonlinear confocal microscopy in isotropic media is derived with Fourier imaging theory and RIKES theory. The impact of nonlinear property of RIKES on the spatial resolution and imaging properties of confocal microscopy have been analyzed in detail. It is proved that RIKES nonlinear confocal microscopy can simultaneously provide more information than two-photon confocal microscopy concerning molecular vibration mode, vibration orientation and optically induced molecular reorientation, etc. It is shown that RIKES nonlinear confocal microscopy significantly enhances the spatial resolution and imaging quality of confocal microscopy and achieves much higher resolution than that of two-photon confocal microscopy.
