Raman band detection apparatus illuminates a sample using an illumination source that oscillates in wavelength over a range. The source might for example switch between two wavelengths or might traverse the wavelength range. A wavelength sensitive detector detects radiation emitted by the sample at a series of different wavelengths and a signal processor extracts signals that have a temporal correspondence to the wavelength variation of the illumination at the different wavelengths. One or more Raman bands that might be present will produce a distinctive characteristic of the extracted signals plotted against a spectral axis and relatively simple processing of these spectrally-related time-varying components can then enhance the appearance of the Raman band in a spectral representation based on the processed components. For example, such processing might comprise numerical integration across a spectral plot of the components, or the selection and shifting of certain components, for instance negative components, to overlie others within portions of the spectral representation showing the presence of the Raman band.