Determination of one-dimensional spherically aberrated point spread function in depth profiling by confocal Raman microscopy
Article first published online: 16 JAN 2013
Copyright © 2013 John Wiley & Sons, Ltd.
Journal of Raman Spectroscopy
Volume 44, Issue 3, pages 447–452, March 2013
How to Cite
de la Paz Miguel, M. and Pablo Tomba, J. (2013), Determination of one-dimensional spherically aberrated point spread function in depth profiling by confocal Raman microscopy. J. Raman Spectrosc., 44: 447–452. doi: 10.1002/jrs.4195
- Issue published online: 19 MAR 2013
- Article first published online: 16 JAN 2013
- Manuscript Accepted: 30 AUG 2012
- Manuscript Revised: 10 JUL 2012
- Manuscript Received: 13 FEB 2012
- confocal Raman microscopy;
- depth profiling;
- point spread function;
We present a simple experiment that allows the complete and direct characterization of the point spread function (PSF) in refraction-aberrated depth profiling experiments with confocal Raman microscopy. We used a wedge-shaped solid polymer film to induce refraction aberrations on the response of an infinitesimally thin Raman scatterer, represented by a polished silicon wafer. The system, with the film pasted on top of the Si wafer, was probed by a depth slicing technique under a dry-optics configuration. Post-acquisition processing of the Si and polymer intensity maps allowed the reconstruction of the axial PSF spatially resolved each 1 µm or less in the z-axis and for virtually continuous values of focusing depth. In agreement with theory, we found that PSF broadens asymmetrically with focusing depth, with a marked shift in the focus point. From the shape of PSF, we obtained values of depth resolution within the film that confirm that axial discrimination is not drastically deteriorated, as suggested by previous works, and that confocal aperture effectively reduces the collection volume even under severe refraction interference. Copyright © 2013 John Wiley & Sons, Ltd.