Laser beam guidance systems and methods

Patent metadata

Field	Value
Publication number	US-9405115-B2
Application number	US-201313843112-A
Country	US
Kind code	B2
Filing date	Mar 15, 2013
Priority date	Apr 10, 2012
Publication date	Aug 2, 2016
Grant date	Aug 2, 2016

Abstract

An automated adaptive optics and laser projection system is described. The automated adaptive optics and laser projection system includes an adaptive optics system and a compact laser projection system with related laser guidance programming used to correct atmospheric distortion induced on light received by a telescope. Control of the automated adaptive optics and laser projection system is designed in a modular manner in order to facilitate replication of the system to be used with a variety of different telescopes. Related methods are also described.

First claim

The invention claimed is:

1. A method comprising:
activating a laser projection system to propagate a laser beam, whereby at least a portion of the laser beam is returned to the system for detection of an error;
configuring an adaptive optics system to detect the detected error to perform a compensating action comprising modifying an operating characteristic of at least one optical component contained in the laser projection system; and
executing a computer-controlled automated acquisition procedure to automatically align the laser projection system, the automated acquisition procedure comprising:
capturing in a wavefront sensor, an image associated with a portion of the projected laser beam returned;
using information obtained by processing the captured image to perform a compensating operation directed at addressing the error; and
executing an iterative routine that comprises:
a) processing the image captured in the wavefront sensor to determine if an overall brightness level in the captured image exceeds an acquisition threshold;
b) when below the acquisition threshold, changing at least one of an orientation or a curvature of a reflecting surface of the laser steering mirror; and
c) repeating steps a) and b) and when equal to or exceeding the acquisition threshold, terminating the iterative routine.

2. The method of claim 1 , wherein the error is a measured distortion of the laser beam being returned to the system, the measured distortion induced by the atmosphere.

3. The method of claim 1 , wherein the automated acquisition procedure comprises an initialization procedure that includes placing a laser steering mirror in a default orientation.

4. The method of claim 1 , further comprising:
providing a telescope configured to observe one or more objects, the telescope being associated with the laser projection system whereby the laser projection system projects a laser beam substantially parallel to a viewing axis of the telescope and the adaptive optics system whereby the adaptive optics system provides corrections to the telescope for distortion caused by the atmosphere based on a measured distortion obtained from a portion of the laser beam returned by the atmosphere by modifying an operating characteristic of at least one optical component contained in at least one of the telescope or the laser projection system.

5. The method of claim 1 , wherein the telescope is also controllable by the automated laser alignment system.

6. The method of claim 1 , wherein the one or more objects observed by the telescope are astronomical objects.

7. The method of claim 1 , wherein modifying the operating characteristic of at least one optical component comprises operating a motor to modify at least one of an orientation of a principal axis of a mirror or a curvature of a surface of the mirror.

8. The method of claim 1 , wherein determining if the overall brightness level in the image exceeds the acquisition threshold comprises:
dividing the processed image into a plurality of segments, each segment forming a corresponding image;
measuring a brightness level of each image corresponding to the plurality of segments.

9. The method of claim 8 , further comprising:
determining a total count of segments each having a segment brightness level exceeding a threshold segment brightness level.

10. The method of claim 9 , further comprising:
using the total count of segments as a parameter to determine if the overall brightness level in the captured image exceeds the acquisition threshold.

11. The method of claim 1 , wherein changing the at least one of an orientation or a curvature of a reflecting surface of the laser steering mirror comprises moving the laser steering mirror in an outward spiraling pattern.

12. The method of claim 1 , wherein the automated acquisition procedure comprises a first acquisition procedure that provides for a coarse level of alignment to the telescope followed by a second acquisition procedure that provides for a fine level of alignment to the telescope.

13. The method of claim 1 , further comprising first checking for a safe operation state before activating the laser projection system.

14. The method of claim 1 , further comprising repetition of the activating and executing steps until all objects are observed or a specified time has elapsed.

Assignees

• California Inst Of Techn

Inventors

• Riddle Reed
• Baranec Christoph

Classifications

• G01J3/0224

  using polarising or depolarising elements · CPC title

• G01J9/00

  Measuring optical phase difference (devices or arrangements for controlling the phase of light beams G02F1/01); Determining degree of coherence; Measuring optical wavelength (spectrometry G01J3/00) · CPC title

• G01J3/027

  Control of working procedures of a spectrometer; Failure detection; Bandwidth calculation · CPC title

• G03B21/2033

  LED or laser light sources · CPC title

• G02B7/003

  Alignment of optical elements (G02B7/001, G02B7/002 take precedence; for mirrors G02B7/1822) · CPC title