Van Duyne group at Northwestern University uses IsoPlane spectrograph to obtain Raman spectra of single rhodamine molecules

Evanston, IL--Determining the origin of relative intensity fluctuations in single-molecule Raman spectroscopic experiments is not easy, but the Van Duyne group at Northwestern University has accomplished this, using an IsoPlane spectrograph from Princeton Instruments (Acton, MA).¹ The group discovered that the changes in mode intensities are completely independent (no correlation); matching the results with theoretical calculations indicate the fluctuations are due to variations in the characteristics of the molecule itself, rather than of the environment surrounding the molecule (diffusion, electromagnetic field gradients, and so on).

The IsoPlane spectrograph is based on a new optical design (which Princeton Instruments is patenting) that eliminates field astigmatism and greatly reduces other aberrations inherent in the design of the Czerny-Turner spectrograph (see this video). It produces images with high spatial resolution across the whole focal plane, rather than only near the center. According to Princeton Instruments, the IsoPlane also eliminates crosstalk in multichannel spectroscopy, providing an 8X increase over comparable instruments in the number of fiber spectra that can be spatially resolved over the height of a CCD array.

REFERENCE:

Sonntag et al., The Journal of the American Chemical Society (2013); doi: 10.1021/ja408758j

For more info, see www.princetoninstruments.com