Lamellar grating structure with polarization-independent diffraction efficiency
AssigneeChromaplex, Inc.
InventorsJohn Hoose, Robert Frankel, Evgeny Popov
Life of this patent
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Abstract
A lamellar volume grating operating in reflection and transmission and providing a substantially wavelength- and polarization-independent diffraction efficiency is disclosed. The lamellar grating has an approximately rectangular grating profile with a height-to-width ratio of the grooves or “teeth” advantageously greater than 2. The grating operates preferably in first order and can be implemented as an immersion grating. In particular, the lamellar volume grating described herein can be employed in an optical multiplexer/demultiplexer arrangement with small overall dimensions.
Claims18
A grating device comprising:
- a volume grating produced in a free surface of a substrate and having a grating period,
- the grating period comprising a first region having a first refractive index of the substrate and a second region having a second refractive index different from the first refractive index, and
- an optically transparent element contacting the free surface of the material which includes the volume grating,
- wherein the substrate is in the form of a prism and the volume grating is produced on an exit face of the prism.
A wavelength-dispersive element comprising:
- a first prism having an entrance face and a first contact face;
- a second prism having an exit face and a second contact face;
- a volume grating produced on one of the first contact face and the second contact face;
- wherein optical radiation impinging on the entrance face is diffracted by the grating towards the exit face with a diffraction efficiency that is substantially independent of the polarization direction of the impinging optical radiation over a predetermined wavelength range.
A method of manufacturing a wavelength-dispersive grating element, comprising:
- producing a volume grating on a contact surface of a first prism;
- and
- bonding a contact surface of a second prism to the contact surface of the first prism that includes the volume grating.
Dependencies are inferred from the claim text.