| 摘要 |
PURPOSE:To generate an evanescent wave of a short wavelength arbitrarily and thereby to improve a lateral resolution or the like by using a concentric- circle-shaped diffraction grating (axicongrating) for an optical probe of an optical near field microscope. CONSTITUTION:Probe light 11 falls in the direction of a vertical arrow. The whole probe light 11 is totally reflected by a grating and an evanescent field is generated on the sample side of the diffraction grating. On the occasion, diffracted light 12 of both +first and -first orders exists. A concentric-circle- shaped diffraction grating generating an evanescent wave is provided for an optical probe and a spot of the evanescent wave being smaller than the wavelength of the light is formed at the center of the diffraction grating. By detecting the interaction of this spot and a sample, a microscopic structure of the sample is measured. In this system, the wavelength of the evanescent wave is determined by the grating interval of the diffraction grating. By narrowing the grating interval, a minute spot of an arbitrary diameter can be obtained by an arbitrary wavelength and thus a high resolution in the lateral direction can be realized. |
