| 摘要 |
A method and apparatus (1) for analysing a sample (1) are provided. The method comprises the steps of: (i) irradiating the sample with a beam of radiation (4) in which at least some of the radiation is incident on the sample at an angle or angles which results in the excitation of surface waves, (ii) exciting surface waves at a surface of the sample, which surface waves are confined to an area having a principal dimension which is comparable to the wavelength of the surface waves, (iii) detecting radiation which includes radiation produced by the surface waves, and (iv) analyzing the detected radiation to obtain information about the sample. The surface waves may be excited over an annulus of the sample surface, achieved by placing the sample at a position off the focal plane of the apparatus. The surface waves may be surface plasmons. The detected radiation may include radiation irradiated from the sample surface which has excited surface plasmons therein and radiation irradiated from the sample surface which has not excited any surface plasmons therein. The signal generated by the combination of these radiations may be combined with a reference beam of radiation by allowing them to interfere with each other, and the overall signal analysed to obtain information about the sample.
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