Hybrid Catadioptric System For Advanced Optical Cavity Velocimetry

• US 20180024230A1
• Filed: 03/17/2014
• Published: 01/25/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: National Security Technologies LLC
• Original Assignee: National Security Technologies LLC
• Inventors: Frayer, Daniel K.
• Granted Patent: US 9,885,613 B1
• Time in Patent Office: Days
• CPC Class Codes: G01J 7/00 Measuring velocity of light
• CPC Class Codes: G01P 3/36 Devices characterised by the use of optical means, e.g. using infrared, visible, or ultraviolet light G01P3/68 takes precedence; gyrometers using the Sagnac effect, i.e. rotation-induced shifts between counter-rotating electromagnetic beams G01C19/64
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems
• CPC Class Codes: G01S 17/89 for mapping or imaging
• CPC Class Codes: G01S 7/4812 transmitted and received beams following a coaxial path
• CPC Class Codes: G01S 7/4813 Housing arrangements
• CPC Class Codes: G01S 7/4818 using optical fibres
• CPC Class Codes: G01S 7/4917 superposing optical signals in a photodetector, e.g. optical heterodyne detection
• CPC Class Codes: G02B 6/322 and having centering means being part of the lens for the self-positioning of the lightguide at the focal point, e.g. holes, wells, indents, nibs
• CPC Class Codes: G02B 6/34 utilising prism or grating G02B6/293 takes precedence

Abstract

A probe including reflector is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface by the probe and then reflected back from the surface, is Doppler shifted by the moving surface, collected into probe, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to one or more lens groups and a reflector, such as a parabolic reflector having a mirrored interior surface.

Claims

1. An optic probe for projecting light rays comprising

a housing defining an interior space between a proximate end and a distal end;

one or more optic signal conductors entering the housing through the proximate end and terminating within the interior space of the housing, the one or more optic signal conductors configured to provide optic signals to the probe;

a reflector having an open distal end and a reflective interior surface;

a first set of lens configured to receive the optic signals and present a first subset of optic signals to at least one second lens and present a second subset of optic signal to the reflector;

one or more additional lenses adjacent the first lens configured to direct the first subset of optic signals through the open distal end of the reflector, wherein the second set of optic signals bypass the one or more additional lenses to reflect from the reflective interior surface of reflector and out the open second end of the reflector.

2. The probe of claim 1 wherein the one or more optic signal conductors are one or more optic fibers.

3. The probe of claim 2 wherein the optic probe for projecting light rays is configured to perform photonic Doppler velocimetry measurement on a surface which receives the projected light rays.

4. The probe of claim 3 wherein the reflector is a parabolic reflector has a mirrored interior surface.

5. The probe of claim 1 wherein the a first set of lens consists of a first lens group and second lens group, both the first lens group and the second lens group being positive, and the one or more additional lenses consists of third lens that is a positive lens.

6. The probe of claim 5 wherein the first set of lenses and the one or more additional lenses are aligned along a central axis and the first set of optic signals exit the reflector at an angle that is closer to the central axis than the angle at which the first set of optic signals exit the reflector.

7. The probe of claim 1 further comprising one or more supports configured to secure the one or more additional lenses within the reflector.

8. The probe of claim 1 wherein the reflector, the one or more additional lenses, and the first set of lenses are configured to receive a surface reflection of the optic signal from a curved surface and conduct the surface reflection back to the optic signal conductor.

9. An optic lens system for projecting light rays comprising

a housing defining an interior space between a first end and a second end;

one or more optic signal conductors configured to carry optic signals, the optic signal comprising a first set of optic signals and a second set of optic signals;

one or more lenses configured to receive at least the first set of optic signals from the one or more optic signal conductors;

a reflector having an open first end and an open second end with a surface extending between the open first end and the open second end and an interior of the surface being reflective, the reflector configured to receive at least the second set of optic signals and reflect the second set of optic signals through the second open end of the reflector at a first angle;

wherein the one or more lenses are configured to project at least the first set of optic signals through the open second end at a second angle, the second angle being different from the first angle.

10. The system of claim 9, wherein the optic signals are projected to a curved surface which is the subject of photonic Doppler velocimetry measurement.

11. The system of claim 10 wherein the reflector and one or more lenses are further configured to receive one or more surface reflections from the curved surface during movement of the curved surface.

12. The system of claim 9 wherein the one or more optic signal conductors comprise one or more optic fibers.

13. The system of claim 9 wherein the housing contains one or more optic signal conductors and one or more lens.

14. The system of claim 9 wherein the one or more lenses comprises a first positive lens group, a second positive lens group and a third positive lens group.

15. The system of claim 9 wherein the first set of optic signals pass through the first positive lens group, a second positive lens group and a third positive lens group while the second set of optic signals pass through the first positive lens group and the second positive lens group but not the third positive lens group.

16. A method, during photonic Doppler velocimetry, for presenting an optic signal to a curved surface and receiving a reflection from the curved surface during movement of the curved surface comprising:

establishing a distal end of a probe facing the curved surface, the probe having a proximate end and distal end including at least one lens and a reflector, the reflector having an open distal end which faces the surface;

generating optic signals;

presenting the optic signals to an optic signal conductor,

passing the optic signal through the optic signal conductor to the at least one lens, the at least one lens separating the optic signals into a first set of optic signals and a second set of optic signals;

reflecting the second set of optic signals from an interior surface of a reflector, the reflecting having a reflective interior surface, the reflected second set of optic signals passing through the open distal end of the reflector toward the surface;

passing the first set of optic signals through the open distal end of the reflector toward the surface;

initiating movement of the curved surface;

receiving one or more surface reflections of the first set of optic signals and the second set of optic signals through the open distal end of the reflector, the surface reflections being reflected from the curved surface;

passing the one or more surface reflections through at least one lens to the optic signal conductor.

17. The method of claim 17 wherein the reflector comprises a parabolic reflector with a mirrored interior surface.

18. The method of claim 17 further comprising processing the optic signals and the surface reflections to perform photonic Doppler velocimetry analysis to monitor movement of the curved surface.

19. The method of claim 17 further comprising passing the optic signal and the surface reflection through a circulator configured to perform as an optical directional coupler.

20. The method of claim 17 wherein the at least one lens consists of a first lens group near the proximate end, and a third lens group near the distal end, and a second lens group between the first lens group and the third lens group, such that the second set of optic signals do not pass through the third lens group.