Thomas L Hartnett

US Patent:

46860703, Aug 11, 1987

Filed:

Oct 29, 1984

Appl. No.:

6/665463

Inventors:

Edward A. Maguire - Ashland MA
Thomas M. Hartnett - Nashua NH
Richard L. Gentilman - Acton MA

Assignee:

Raytheon Company - Lexington MA

International Classification:

C04B 3558

US Classification:

264 12

Abstract:

A method of preparing substantially homogeneous aluminum oxynitride powder is provided comprising the steps of reacting gamma aluminum oxide with carbon in the presence of nitrogen, and breaking down the resulting powder into particles in a predetermined size range. A method of preparing a durable optically transparent body from this powder is also provided comprising the steps of forming a green body of substantially homogeneous cubic aluminum oxynitride powder and sintering said green body in a nitrogen atmosphere and in the presence of predetermined additives which enhance the sintering process. Preferred additives are boron, in elemental or compound form, and at least one additional element selected from the group of yttrium and lanthanum or compounds thereof. The sintered polycrystalline cubic aluminum oxynitride has a density greater than 99% of theoretical density, an in-line transmission of at least 50% in the 0. 3-5 micron range, and a resolving angle of 1 mrad or less.

US Patent:

20230052113, Feb 16, 2023

Filed:

Aug 11, 2021

Appl. No.:

17/399510

Inventors:

- Waltham MA, US
Gerhard Sollner - Lincoln MA, US
Jason D. Adams - Medway MA, US
Poornima Varadarajan - Westford MA, US
Thomas M. Hartnett - Nashua NH, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

H01P 1/22
H01P 1/203
H03H 7/01

Abstract:

Methods and apparatus for a frequency selective limiter (FSL) having a magnetic material substrate that tapers in thickness and supports a transmission line that has segments and bends. The segments, which differ in width and are substantially parallel to each other, such that each segment traverses the substrate on a constant thickness of the substrate.

US Patent:

20140231727, Aug 21, 2014

Filed:

Sep 20, 2013

Appl. No.:

14/032958

Inventors:

- Waltham MA, US
Richard Gentilman - Acton MA, US
Christopher Scott Nordahl - Littleton MA, US
Thomas M. Hartnett - Nashua NH, US

Assignee:

Raytheon Company - Waltham MA

International Classification:

G02B 1/00

US Classification:

252582

Abstract:

A solid solution-based optical material capable of transmitting infrared light, the solid solution-based optical material comprising at least two nano-sized phases intermixed in one another, wherein at least one of the at least two nano-sized phases is a solid solution containing a dissolved dopant, the dissolved dopant present in an amount sufficient to reduce a refractive index difference between the at least two nano-sized phases to about 0.2 or less when infrared light is being transmitted. Various embodiments are directed to related systems and methods. In one embodiment, the infrared light is visible infrared light, short-wave infrared light, eye safe infrared light, medium wave infrared light, long wave infrared red light, or combinations thereof.