Patent ID: 7042556

Claim:
A method for depth-resolved detection of subsurface micro-structure and features in a sample, said method comprising: a) producing a first illumination of the sample with light possessing polarization in a first direction of polarization creating a first diffraction limited focal point within the sample; b) measuring light intensity emanating from the first diffraction limited focal point resulting from said first illumination that is polarized in a second direction of polarization; c) changing the relative position and orientation of the first diffraction limited focal point and the sample in one or more directions; d) producing a second illumination of the sample with light possessing polarization in the first direction of polarization creating a second diffraction limited focal point directed within the sample; e) measuring light intensity emanating from the second diffraction limited focal point resulting from said second illumination that is polarized in the second direction of polarization; and f) multiplying the measured light intensity emanating from said first diffraction limited focal point by a factor compensating for attenuation of light within said sample material; g) multiplying the measured light intensity emanating from said second diffraction limited focal point by a factor compensating for attenuation of light within said sample; h) comparing emanating light intensity between said first diffraction limited focal point and said second diffraction limited focal point.