Abstract: A method of smoothing spectral data recorded by a spectrometer including successively fitting a plurality of spline curves to the spectral data, each spline curve having a different number of knots. A knot position of each knot, other than end point knots, in each spline curve is determined based upon a measure of fit of points of a previously fitted one of the spline curves having fewer knots to the spectral data. The method further includes selecting one of the spline curves as a smoothed data curve of the spectral data based upon a model selection criterion.

Abstract: A method of determining components present in a sample from spectral data obtained from the sample including resolving each of a plurality of models of the spectral data, the plurality of models including models having a different number of component reference spectra selected from a set of predetermined component reference spectra; selecting a one of the plurality of models based upon a model selection criterion and determining one or more components present in the sample based upon the selected model. The model selection criterion includes a measure for each model, which balances improvements in fit quality of the model to the spectral data against a complexity penalty determined from the number of component reference spectrum used in the model.

Abstract: An optical device includes a unitary substrate of optically transparent material. The unitary substrate has formed therein at least one collection lens and channel, the channel for receiving an optical fibre and arranged to align the optical fibre inserted therein such that the collection lens couples light collected by the collection lens into the optical fibre.

Abstract: A method of smoothing spectral data recorded by a spectrometer including successively fitting a plurality of spline curves to the spectral data, each spline curve having a different number of knots. A knot position of each knot, other than end point knots, in each spline curve is determined based upon a measure of fit of points of a previously fitted one of the spline curves having fewer knots to the spectral data. The method further includes selecting one of the spline curves as a smoothed data curve of the spectral data based upon a model selection criterion.

Abstract: An optical device includes a unitary substrate of optically transparent material. The unitary substrate has formed therein at least one collection lens and channel, the channel for receiving an optical fibre and arranged to align the optical fibre inserted therein such that the collection lens couples light collected by the collection lens into the optical fibre.

Abstract: A method of estimating background radiation in spectral data. The method may comprise, iteratively, fitting an analytical curve, such as a spline curve, to reference data, determining an allowable deviation of the reference data from the analytical curve and clipping data points of the reference data or the spectral data that are more than the allowable deviation above the analytical curve to provide the reference data for the next iteration until termination criterion is met. The reference data is initially based upon the spectral data. The method may comprise generating estimates of background radiation of the spectral data, each estimate based upon fitting a different order polynomial to the spectral data, and selecting an order of polynomial to use for estimating background radiation and/or one of the estimates of the background radiation. The method may further comprise estimating the noise in the spectral data from the reference data.

Abstract: Spectroscopy including a source generating light profile on the sample. The light profile is movable relative to the sample. An optical input for receiving light from sample interaction with light from the source, a detector including two-dimensional array of photodetector elements, a dispersive device between the optical input and detector to spectrally disperse light from the optical input in spectral direction across the detector, an optical splitter in optical path between the optical input and detector to split light based upon wavenumber so, for a spectrum generated by a point on the sample, the spectrum first and second portions are dispersed across photodetector elements of different array row/column.

Abstract: This invention concerns a spectroscopic method, apparatus for determining whether a component is present in a sample. In one aspect, the method includes resolving a model of the spectral data separately for candidates from a set of predetermined component reference spectra, and determining whether a component is present in the sample based upon a figure of merit quantifying an effect of including the candidate reference spectrum corresponding to that component in the model.

Abstract: A method of estimating background radiation in spectral data. The method may comprise, iteratively, fitting an analytical curve, such as a spline curve, to reference data, determining an allowable deviation of the reference data from the analytical curve and clipping data points of the reference data or the spectral data that are more than the allowable deviation above the analytical curve to provide the reference data for the next iteration until termination criterion is met. The reference data is initially based upon the spectral data. The method may comprise generating estimates of background radiation of the spectral data, each estimate based upon fitting a different order polynomial to the spectral data, and selecting an order of polynomial to use for estimating background radiation and/or one of the estimates of the background radiation. The method may further comprise estimating the noise in the spectral data from the reference data.

Abstract: A Raman spectroscopy system has a filter arrangement comprising two filters (16, 26A) in series, to reject light of the illuminating wavenumber from the scattered light of interest. The filters are tilted and have different characteristics for light of first and second different polarisation states. To counter this, the filters are arranged so that their respective effects on the respective polarisation states at least partially cancel each other out. This may for example be done by arranging their tilt axes (32, 34) orthogonally to each other.

Abstract: A sample is illuminated by laser light and the resulting Raman spectrum is dispersed at a high spectral resolution along one or more rows or columns of detector elements of a CCD. The resulting charge is shifted in a direction Y? and binned in an output register of the CCD. The dispersed spectrum is moved along the rows or columns in a direction X?, synchronously with the shifting of charge in the output register. Thus, data from a given wavenumber in the spectrum continues to accumulate in the output register during the movement. This enables data from a wide spectrum to be collected at high resolution, without the need to subsequently stitch blocks of data together in a computer, even where the CCD is arranged such that row-by-row transfer of charge towards the output register is orthogonal to the direction of dispersion.

Abstract: A sample (26) is illuminated by laser light and the resulting Raman spectrum (62) is dispersed at a high spectral resolution along one or more rows or columns of detector elements (60) of a CCD (34). The resulting charge is shifted in a direction Y? and binned in an output register 64 of the CCD. The dispersed spectrum is moved along the rows or columns in a direction X?, synchronously with the shifting of charge in the output register (arrow 72). Thus, data from a given wavenumber in the spectrum continues to accumulate in the output register during the movement. This enables data from a wide spectrum to be collected at high resolution, without the need to subsequently stitch blocks of data together in a computer, even where the CCD is arranged such that row-by-row transfer of charge towards the output register is orthogonal to the direction of dispersion.

Abstract: A sample positioning stage for positioning a sample to be inspected relative to an optical inspection device, including a first generally planar body on which a sample can be carried and a second body directly coupled to the first body via at least one rigid bearing and at least one resiliently compliant bearing provided between the first and second bodies. The first and second bodies are preloaded against each other in a dimension substantially parallel to the plane of the first generally planar body via the bearings. The stage also includes a motorized drive system operable to drive the first and second bodies relative to each other in the first plane toward a demanded relative position received from a position input device, and a position sensing device on at least one of the first and second bodies, for providing a measure of the relative position of the first and second bodies.

Abstract: A Raman spectroscopy system has a filter arrangement comprising two filters (16, 26A) in series, to reject light of the illuminating wavenumber from the scattered light of interest. The filters are tilted and have different characteristics for light of first and second different polarisation states. To counter this, the filters are arranged so that their respective effects on the respective polarisation states at least partially cancel each other out. This may for example be done by arranging their tilt axes (32, 34) orthogonally to each other.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the center of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the centre of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: The invention relates to a method and apparatus for focusing structured image such as a laser spot. A method for determining the degree of focus of such a structured image are disclosed whereby: an image is provided at a photosensitive array formed from a plurality of elements; the position of the image is determined; for an element of the array a weighting is assigned according to the position of that element relative to the position of the image; the intensity of the image at the element is determined; a value is produced for the element dependent on its weighting and the intensity of the image thereat. In addition the values of the plurality of elements are summed and one overall focus value is found which is indicative of the degree of focus of the image. This value is used to search for and maintain best focus and methods for achieving this are disclosed also. Apparatus is shown in which a microprocessor and a controller are used to perform the methods disclosed.