Spatial-domain low-coherence quantitative phase microscopy

A spatial-domain low-coherence quantitative phase microscopy method, comprising:

• producing white light from a light source;
• tuning the white light with an acousto-optical tuned filter (AOTF);
• projecting the tuned light onto a sample, wherein the sample scatters at least a portion of the tuned light back;
• recording the scattered portion of the tuned light with a camera;
• and
• measuring the recorded scattered portion including quantifying changes in optical path length at a plurality of predetermined depth locations within the sample below a surface of the sample and generating a depth-resolved three-dimensional structural feature vector based at least in part on the quantified changes in optical path length and determining sub-resolution axial nanoscale structural changes in the sample based at least in part on the depth-resolved three-dimensional structural feature vector, wherein a distance between each of the predetermined depth locations is at least one coherence length of a correlation function of the light source.

A spatial-domain low-coherence quantitative phase microscopy apparatus, comprising:

• means for producing white light from a light source;
• means for tuning the wavelength of white light;
• means for projecting the tuned light onto a sample, wherein the sample scatters at least a portion of the light back;
• means for recording the scattered portion;
• means for measuring the recorded light;
• means for generating a depth-resolved three-dimensional structural feature vector at a set of a plurality of predetermined depth locations based at least in part on the measured recorded light;
• and
• means for determining sub-resolution axial nanoscale structural changes in the sample based at least in part on the depth-resolved three-dimensional structural feature vector including by quantifying changes in optical path length at the plurality of predetermined depth locations to remove an effect of a thickness of the sample, wherein a distance between each of the predetermined depth locations is at least one coherence length of a correlation function of the light source.