Narrow band algan filter
AssigneeAPA Optics, Inc.
InventorsMuhammad A. Khan, Jonathon N. Kuznia, James M. Van Hove
Life of this patent
Estimating the term…
Abstract
The invention is a filter device of at least two layers, the first layer of Al.sub.x Ga.sub.(1-x) N and the second layer of Al.sub.y Ga.sub.(1-y) N wherein x and y may have any value from 0 to 1. The invention may be used as a fixed wavelength or tunable wavelength filter or in ultraviolet detectors and laser devices, among other systems. Applications for the invention include detection of UV radiation in environments having a high level of incident infrared and visible radiation, as well as applications requiring detection of UV emission when no other radiation is present.
Claims24
A filter device of at least two layers, said first layer comprising
- Al.sub.x Ga.sub.(l-x) N
- wherein x has a value ranging from about 0 to 1, and said device second layer comprising
- Al.sub.y Ga.sub.(l-y) N
- wherein y has a value ranging from about 0 to 1, said filter device having a band width determined by .gamma./4=n.sub.l d.sub.l =n.sub.2 d.sub.2 wherein .gamma. is the wavelength of the energy to be transmitted through the filter, n.sub.l is the refractive index of said first layer, n.sub.2 is the refractive index of said second layer, d.sub.l is the thickness of said first layer and d.sub.2 is the thickness of said second layer.
A detector device comprising:
- (a) an ultraviolet detector;
- and
- (b) a filter device of at least two layers, said first layer comprising
- Al.sub.y Ga.sub.(l-x) N
- wherein x has a value ranging from about 0 to 1, and said device second layer comprising
- Al.sub.y Ga.sub.(l-y) N
- wherein y has a value ranging from about 0 to 1, said filter device having a band width determined by .gamma./4=n.sub.1 d.sub.1 =n.sub.2 d.sub.2 wherein .gamma. is the wavelength of the energy to be transmitted through the filter, n.sub.1 is the refractive index of said first layer, n.sub.2 is the refractive index of said second layer, d.sub.1 is the thickness of said first layer and d.sub.2 is the thickness of said second layer.
A method of forming a filter device of at least two layers, said first layer comprising Al.sub.x Ga.sub.(l-x) N wherein x has a value ranging from 0 to 1, said device second layer comprising Al.sub.y Ga.sub.(l-y) N wherein y has a value ranging from about 0 to 1, said method comprising the step of determining the band width of a given layer by .gamma./4=n.sub.1 d.sub.1 =n.sub.2 d.sub.2 wherein .gamma. is the wavelength of the energy to be transmitted through the filter, n.sub.1 is the refractive index of said first layer and n.sub.2 is the refractive index of said second layer, d.sub.1 is the thickness of said first layer and d.sub.2 is the thickness of said second layer.
Dependencies are inferred from the claim text.