Thin film type optical collimator on basis of surface plasmon polaritons

Abstract

The invention relates to a thin film type optical collimator on the basis of surface plasmon polaritons, which is formed by a substrate and a metal grating. The substrate is a glass substrate for bearing the metal grating; and the metal grating is formed by a metal medium alternate film and a metal surface grating structure, wherein the metal medium alternate film is obtained by alternately making a metal thin film and a medium thin film on the substrate by a vacuum hot dip coating technology or a magnetron sputtering technology and the metal surface grating structure is made on the metal medium alternate film by a two-beam interference exposure technology and a stripping technology. The structure changes Gaussian light into planar light by utilizing the metal medium alternate film for the first time and also has capacity of expanding the light beam width; the structure is compact, the size is small and the total thickness of a device is used as a wavelength magnitude; on the basis that the metal medium alternate film which adopts a simple preparation process and is low in cost supports the metal surface grating and conducts light, a metal film with a through hole, which is high in manufacturing cost, is avoided; and the thin film type optical collimator can be integrally made on the end faces of a semiconductor laser, a light emitting diode, an optical fiber or an optical fiber laser, and is used for improving an angle of divergence of a light beam and obtaining collimated light.

Description

technical field [0001] The invention relates to a light collimator in the field of photonics, more specifically, it is a kind of surface plasmon polaritons (Surface Plasmon Polaritons) excited by the composite structure of metal dielectric alternating film and metal surface grating to reduce the incident Gauss The divergence angle of the beam can be adjusted to obtain a thin-film light collimator for the outgoing beam that propagates close to the form of planar light. Background technique [0002] The function of the optical collimator is to change the light beam with a large divergence angle in the far field into a light beam with a small divergence angle, making it close to planar light. Wide range of applications. Currently, known light collimation devices are composed of traditional components such as lens groups or aspheric optical elements. For example, the published U.S. patents US4995709 (optical collimator), US7580192 (Collimation lens system for led) and Chinese ...

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Problems solved by technology

However, the structure of this device is more complex and requires the use of overlay and other manufacturing processes to obtain

[0010] In addition, the surface wave emitted from the metal via and the surface wave emitted from the exit grating have different distributions and intensities. In order to mak...

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