Optical waveguide

Abstract

When light is made to enter an optical waveguide 14 formed through a device body 12 made of silver (Ag) serving as a plasmon active medium, surface plasmons are generated on a defined surface 55 of the optical waveguide 14 (including a micro opening 16). Therefore, the intensity of light propagated through the optical waveguide 14 increases as the light travels toward the micro opening 16. The end of a first projecting piece 13a projects further than the end 52 of a second projecting piece 13b. Consequently, the light is focused at around the first projecting piece 13a according to the intensity distribution of the electric field around the end of the projecting portion 13. Therefore, the light exuding from the micro opening 16 is prevented from spreading in the direction of polarization of the light. As a result, the intensity of light propagated through the optical waveguide 14 can be increased at low cost without inviting an increase of the spread of the light while maintaining good S / N ratio.

Description

technical field [0001] The present invention relates to an optical waveguide device suitable for use in a scanning near-field optical microscope or an optical information recording device or the like. Background technique [0002] In recent years, as a technology that can perform optical processing in a field smaller than the wavelength of light (visible light: 0.4 to 0.8 microns), the use of near-field light (light transmitted only in a region shorter than the wavelength of light) Technology is attracting attention. For example, in the field of scanning near-field optical microscopy, as described in Japanese Patent Document 1 "JP-A-2002-221478", an optical probe having a micro opening smaller than the wavelength of light at the tip is used as an optical waveguide. device. When observing a minute region on the surface of a sample, the minute opening of the optical probe is placed close to the minute region to be observed so that the light field (near field) seeping into th...

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Problems solved by technology

However, when the tip of a non-aperture probe is actually inserted into the near-field light region, scattered light is generated not only at the tip of the probe but also at parts other than the tip of the probe.

Therefore, the S / N ratio (signal / noise ratio) of the non-aperture probe is worse than that of the opening probe, which may reduce the detection sensitivity

In addition, when using a non-aperture probe, it is necessary to prepare an optical probe for detection separately, and the cost will increase

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