Renishaw Plc

Ian P Hayward

David N Batchelder

Robert Bennett

Chunwei Cheng

Brian J E Smith

Kurt J Baldwin

In a Raman spectroscopy apparatus, exciting light is focussed on a sample () as a line focus. Spectra from points in the line focus are dispersed in rowson a CCD detector, having a two-dimensional array of pixels. The line focus moves longitudinally in a direction Y (arrow) relative to the sample. Simultaneously and synchronously, charge is shifted in a parallel direction Y' (arrow) within the CCD, so that data from a given point in the sample continues to accumulate. This ensures that the data from each sample point arises from illumination which is integrated along the line focus, and makes it easier to stitch the data together subsequently to form an image of the sample. In order to provide averaging in the X direction during fast, low resolution scanning, the line focus is swept across the sample in a zig-zag fashion, between boundary lines

Spectroscopic apparatus with dispersive device for collecting sample data in synchronism with relative movement of a focus

In a Raman microscope, Raman scattered light from an illuminated area on a sample 10 is collected by an objective 12 and imaged by a lens 18 onto a detector in an image plane 20. A filter 16 selects only light of a desired Raman wavenumber shift. Since the tuning of this filter is sensitive to the angle of incidence, it is placed after the lens 18 instead of before it, and the distance from the objective 12 to the lens 18 is made substantially equal to the focal length of the lens 18. This ensures that chief rays 14A',14B' from different points on the sample 10 pass through the filter 16 at the same angle of incidence. The wavenumber selected by the filter is therefore the same for light from all points on the sample, which it would not be if the filter were placed before the lens 18.

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Warminster, United Kingdom

Ian P Hayward