Michael J Duncan

US Patent:

6049381, Apr 11, 2000

Filed:

Oct 29, 1993

Appl. No.:

8/143370

Inventors:

John F. Reintjes - Alexandria VA
Michael D. Duncan - Cheverly MD
Rita Mahon - Silver Spring MD
Lawrence L. Tankersley - Annapolis MD
Paul L. Howard - West Chester PA
Martin Chamberlain - Arlington VA
Thomas McKenna - Arlington VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G01N 2105

US Classification:

356335

Abstract:

A method and apparatus for real-time monitoring of particulates in a fluid. The fluid is illuminated, and an image formed of the interior of the fluid. The image is then detected, and processed to determine the size, shape, etc. of particulates within the fluid.

US Patent:

52751686, Jan 4, 1994

Filed:

Mar 31, 1992

Appl. No.:

7/861213

Inventors:

John F. Reintjes - Alexandria VA
Michael D. Duncan - Cheverly MD
Rita Mahon - Silver Spring MD
Lawrence L. Tankersley - Annapolis MD
Ronald W. Waynant - Laurel MD
Mark Bashkansky - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

A61B 600

US Classification:

128665

Abstract:

An apparatus for the time-gated optical examination of objects that are p of, embedded in or viewed through dense scattering materials is disclosed. In a preferred embodiment, the apparatus comprises: a light source for producing a first light pulse and a pump light pulse, each of the first and pump light pulses having a preselected pulse width at a preselected pump wavelength; a Raman generator for shifting the wavelength of the first light pulse to a preselected Stokes wavelength to form Stokes light; a first optical train for transmitting the Stokes light through the dense scattering material to obtain Stokes light comprised of a relatively small, image-bearing signal component including unscattered Stokes light or Stokes light with minimal deviation due to scattering, light followed in time by a relatively large amount of light scattered by the dense scattering material; a Raman amplifier; an optical system for transporting the Stokes light from the dense scattering material to the Raman amplifier; a variable delay path disposed between the light source and the Raman amplifier for varying the transit time of the pump pulse to cause the pump pulse to overlap in time with the signal component of Stokes light at the Raman amplifier, the Raman amplifier only amplifying the signal component of Stokes light that is overlapped in time by the pump pulse; and a two-dimensional detector for detecting the amplified signal component of Stokes light.

US Patent:

60348046, Mar 7, 2000

Filed:

Mar 31, 1998

Appl. No.:

9/050964

Inventors:

Mark Bashkansky - Alexandria VA
Michael Duncan - Cheverly MD
John Reintjes - Alexandria VA

Assignee:

The United States of America as represented by the Secretary of the Navy - Washington DC

International Classification:

G02B 2608

US Classification:

359201

Abstract:

A scanning system for scanning in first and second dimensions a desired surface topology of a sample, the scanning device comprising: a light source for producing a collimated light beam; a first scanning device responsive to the collimated light beam from the light source for producing a first scanned beam in a first dimension with a constant optical path length; and a second scanning device coupled between the first scanning device and the sample for focusing and scanning the first scanned beam in a second dimension onto the surface region of the sample to cause the collimated light beam to scan the surface topology of the sample with a constant optical path length in each of the first and second dimensions of the desired topology of the sample. In a second embodiment of the invention, a beam of light is focused by a first lens before a scanner and the scanner is rotated. Second and third lenses arranged in a 4-f combination are used to image rotated focal spots along a spherical convex surface of a sample while the optical path length stays constant.