Device to control the aiming and focusing of laser systems on a target

• US 6,040,566 A
• Filed: 01/20/1998
• Issued: 03/21/2000
• Est. Priority Date: 01/31/1997
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF (Thales SA)
• Original Assignee: Thomson-CSF (Thales SA)
• Inventors: Thibout, Paul, Jano, Patrice, Rioland, Jacques
• Primary Examiner(s): Westin, Edward P.
• Assistant Examiner(s): Luu, Thanh X.
• Application Number:
  US09/009,180
• Time in Patent Office: 791 Days
• Field of Search: 250/201.9, 250/201.8, 250/203.2, 356/121, 356/363
• US Class Current: 250/201.9
• CPC Class Codes: G21B 1/23 Optical systems, e.g. for irradiating targets, for heating plasma or for plasma diagnostics
• CPC Class Codes: Y02E 30/10 Nuclear fusion reactors

Abstract

A device to control the aiming and focusing of laser systems on a target comprises at least one reflecting false target (21) positioned and oriented substantially identically to the target (3), a lens (12) for the focusing of the beam on this false target, a separator device (11), a wavefront analyzer (35), a mirror (33) and a semi-reflective plate (32), the beam (1) getting focused, at the end of the system, on the false target (21) after getting reflected on the separator device (11). A part (31) of the beam with the same wavelength as that of the part reflected by the separator device (11) goes through this device and the semi-reflective plate (32) to get directed towards the wavefront analyzer (35). The beam reflected by the false target (21) goes through the separator grating (11) to get reflected on the mirror (33) and the semi-reflective plate (32) to get directed towards the wavefront analyzer (35). The aiming and focusing measurements are carried out by means of this wavefront analyzer (35) through a differential analysis between the two wavefronts. Application especially to power lasers.

Claims

1. A device for aiming and focusing a laser beam on a target, said device comprising:

at least one reflecting false target positioned and oriented substantially identically to a target to be impinged by a laser beam;

a separator device configured to receive the laser beam, transmit a first portion of the laser beam having a first wavefront, and reflect a second portion of the laser beam having a second wavefront, said first wavefront and said second wavefront having substantially the same wavelength;

a lens configured to receive the second portion of the laser beam reflected by the separator device and to focus the second portion of the laser beam on the reflecting false target;

a first mirror configured to receive the second portion of the laser beam reflected off of the reflecting false target and to reflect the second portion of the laser beam;

a second mirror configured to receive the second portion of the laser beam reflected off of the first mirror, reflect the second portion of the laser beam, receive the first portion of the laser beam transmitted by the separator device, and transmit the first portion of the laser beam, said second mirror being a semi-reflective mirror; and

a wavefront analyzer configured to receive the first portion of the laser beam transmitted by the separator device, receive the second portion of the laser beam reflected by the second mirror, and make aiming and focusing measurements for t he laser beam by performing a differential analysis of the first wavefront and the second wavefront.

2. A device according to claim 1, wherein the wavefront analyzer comprises:

a Hartmann analyzer.

3. A device according to claim 1, wherein the transversal and longitudinal positioning of the laser beam on the false target is measured by analyzing the differential imprint of the first and second portions of the laser beam on the wavefront analyzer.

4. A device according to claim 1, wherein the wavelength of the laser beam when the laser beam is reflected off of the reflecting false target is the same as the wavelength of the laser beam when the laser beam is to impinge the target.

5. A device according to claim 1, wherein the false target comprises:

one or more reflective spherical surfaces, centered on specified focusing points positioned and oriented identically to the real target.

6. A device according to claim 5, wherein the false target comprises:

a cylinder having two ends and a sphere on each of the two ends.

7. A device according to claim 5, wherein the false target comprises:

a cylinder having two ends and a hemisphere on each of the two ends.

8. A device according to claim 1, wherein the wavefront analyzer is connected to means for driving a wavefront corrector implanted in the system.

9. A device for aiming and focusing a laser beam on a target, said device comprising:

at least one reflecting false target positioned and oriented substantially identically to a target to be impinged by a laser beam;

separator means for receiving the laser beam, transmitting a first portion of the laser beam having a first wavefront, and reflecting a second portion of the laser beam having a second wavefront, said first wavefront and said second wavefront having substantially the same wavelength;

lens means for receiving the second portion of the laser beam reflected by the separator means and for focusing the second portion of the laser beam on the reflecting false target;

first mirror means for receiving the second portion of the laser beam reflected off of the reflecting false target and for reflecting the second portion of the laser beam;

second mirror means for receiving the second portion of the laser beam reflected off of the first mirror means, reflecting the second portion of the laser beam, receiving the first portion of the laser beam transmitted by the separator means, and transmitting the first portion of the laser beam; and

wavefront analyzer means for receiving the first portion of the laser beam transmitted by the second mirror means, receiving the second portion of the laser beam reflected by the second mirror means, and making aiming and focusing measurements for the laser beam by performing a differential analysis of the first wavefront and the second wavefront.