Optical grating and method of manufacture
AssigneeWestern Digital (Fremont), LLC
InventorsZhongyan Wang, Wei Gao, Ruolin Li, HongXing Yuan, Jinshan Li
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Abstract
A method and system for providing an optical grating are described. The optical grating is configured for light of a wavelength and includes a first optically transparent layer, a stop layer on the first optically transparent layer, and a second optically transparent layer on the stop layer. The first optically transparent layer is continuous and includes a material. The second optically transparent layer also includes the material. The second optically transparent layer also includes a plurality of discrete ridges spaced apart by a pitch. The stop layer is configured to be invisible to the light.
Claims21
An optical grating configured for light of a wavelength, the optical grating comprising:
- a first optically transparent layer, the first optically transparent layer being continuous and including a material;
- a stop layer on the first optically transparent layer, the stop layer having a thickness of not more than ten percent of the wavelength such that the stop layer is invisible to the light;
- and
- a second optically transparent layer on the stop layer, the second optically transparent layer including the material and a plurality of discrete ridges spaced apart by a pitch.
A method for providing an optical grating configured for light a wavelength, the method comprising:
- providing a first optically transparent layer including a material;
- providing a stop layer on the first optically transparent layer, the stop layer having a thickness of not more than ten percent of the wavelength such that the stop layer is invisible to the light
- providing a second optically transparent layer on the stop layer, the second optically transparent layer including the material;
- removing a portion of the second optically transparent layer via a removal process, the stop layer being a stop for the removal process, the removal process leaving a plurality of discrete ridges interleaved with a plurality of troughs, the plurality of discrete ridges spaced apart by a pitch.
A method for providing an optical grating configured for light a wavelength, the method comprising:
- providing a first optically transparent layer including a material;
- providing a stop layer on the first optically transparent layer, the stop layer being configured to be invisible to the light
- providing a second optically transparent layer on the stop layer, the second optically transparent layer including the material;
- removing a portion of the second optically transparent layer via a removal process, the stop layer being a stop for the removal process, the removal process leaving a plurality of discrete ridges interleaved with a plurality of troughs, the plurality of discrete ridges spaced apart by a pitch, the step of removing a portion of the second optically transparent layer further including
- providing a mask including a plurality of lines interspersed with a plurality of apertures, the plurality of apertures exposing the portion of the second optically transparent layer;
- and
- etching the portion of the second optically transparent layer to provide the plurality of discrete ridges, the etching terminating at the stop layer;
- and
- wherein the second optically transparent layer has a first substantially uniform thickness and the mask has a second substantially uniform thickness.
Dependencies are inferred from the claim text.