Depth resolution capabilities using optical standing waves near surfaces


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The physics of standing waves has been explored for more than 50 years. Standing wave fields can be used to selectively enhance luminescence or enhance the Raman signal. We explore here the optical standing wave field with optical scanning probes in collection mode at variable distances from the surface and using no feedback signal. The complex image contrast due to diffraction can be explained by the formation of surface and lateral standing waves. While the lateral fringe spacing depends sensitively on distance between the image plane and the surface, the shape of the lateral standing waves depends on the scattering vector and the index of reflection. Scanning in the intermediate field range has the advantage that the transverse field component is larger than the longitudinal field component. This reduces probe induced effects in the recorded image. The lateral resolution is below the diffraction limit and comparable to nearfield optical techniques when scanning in the intermediate field range. We explore here the depth resolution capabilities when analysing optical standing waves near surfaces and study the influence of the finite penetration length of the light into the substrate. Understanding in the formation of optical standing waves near surfaces opens opportunities to develop new interferometric encryption techniques.

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Journal: TechConnect Briefs
Volume: 1, Technical Proceedings of the 2007 NSTI Nanotechnology Conference and Trade Show, Volume 1
Published: May 20, 2007
Pages: 149 - 151
Industry sectors: Advanced Materials & Manufacturing | Sensors, MEMS, Electronics
Topics: Nanoelectronics, Photonic Materials & Devices
ISBN: 1-4200-6182-8