Multi-color, multi-pulse laser

• US 6,199,794 B1
• Filed: 08/22/1977
• Issued: 03/13/2001
• Est. Priority Date: 03/17/1975
• Status: Expired due to Term

• Current Assignee: Charles S. Naiman, Stuart D. Pompian
• Original Assignee: Charles S. Naiman, Stuart D. Pompian
• Inventors: Pompian, Stuart D., Naiman, Charles S.
• Primary Examiner(s): Moskowitz, Nelson
• Application Number:
  US05/821,122
• Time in Patent Office: 8,604 Days
• Field of Search: 244/3.13, 244/3.16, 250/341, 250/342, 250/199, 250/203, 250/494, 343/17.2 R, 343/6, 362/110-112, 362/259, 356/152, 89/41 SW, 331/94.5 R
• US Class Current: 244/3.16
• CPC Class Codes: F41G 3/145 using a target illuminator
• CPC Class Codes: F41G 7/226 Semi-active homing systems, i.e. comprising a receiver and involving auxiliary illuminating means, e.g. using auxiliary guiding missiles
• CPC Class Codes: F41G 7/2293 using electromagnetic waves other than radio waves
• CPC Class Codes: G03H 1/02 Details of features involved during the holographic process; Replication of holograms without interference recording
• CPC Class Codes: G03H 2001/0212 Light sources or light beam properties G03H1/06, G03H1/24 take precedence; corresponding details, see subgroups of G03H2222/00
• CPC Class Codes: G03H 2222/13 Multi-wavelengths wave with discontinuous wavelength ranges G03H2222/18 takes precedence
• CPC Class Codes: G03H 2222/33 Pulsed light beam
• CPC Class Codes: H01S 3/08054 Passive cavity elements acting on the polarization, e.g. a polarizer for branching or walk-off compensation quarter-wave plates in a Q-switch laser H01S3/1124, H01S3/115
• CPC Class Codes: H01S 3/0809 Two-wavelenghth emission
• CPC Class Codes: H01S 3/0813 Configuration of resonator
• CPC Class Codes: H01S 3/082 defining a plurality of resonators, e.g. for mode selection or suppression
• CPC Class Codes: H01S 3/115 using intracavity electro-optic devices
• CPC Class Codes: H01S 3/127 Plural Q-switches

Abstract

A multi-color, multi-pulse laser target designator is disclosed in which the target is illuminated with pulses of preselected colors and interpulse spacings so as to uniquely identify the target. Inter-pulse spacing may be varied down to an arbitarily small spacing by virtue of the use of pulses of differing colors, thereby increasing countermeasure resistance due to the difficulty of a target detecting and duplicating inter-pulse spacing. Pulse elongation is provided in one embodiment to provide prolonged illumination of the target so as to permit increased homing accuracy for optically guided weapons.

Claims

1. A method for designating a target comprising:

illuminating a target with multiple laser pulses (of) of differing colors, said pulses having spacings between pulses unique to a known illuminating means and variable down to a predetermined small spacing, and elongating one of said pulses, whereby pulses reflected by said target having said unique pulse spacings designate the target as the one illuminated by said known illuminating means and whereby said pulse spacings may be made small enough such that the multiple pulse nature is difficult to detect for those not initially aware of the multiple pulse nature of the illumination.

2. A method for designating a target comprising:

providing a source of multiple differently colored pulses of electromagnetic radiation from a single rod multiple cavity laser having sequentially actuated Q-switches one each to a cavity such that the inter-pulse spacing is of a predetermined small spacing;

illuminating a target with said multiple differently colored pulses, said pulses having pulse spacings unique to a known illuminating source set by said sequential actuation; and

detecting electromagnetic radiation having said unique pulse spacings from a reflective object, whereby said object is designated as the one illuminated by said known illuminating source, and whereby said pulse spacings is small enough such that the multiple pulse nature is difficult to detect for those not initially aware of the multiple pulse nature of the illumination.

3. A system for designating a target, comprising:

means for illuminating a target with multiple differently colored pulses of electromagnetic radiation, said means including a single rod, multiple cavity laser having sequentially actuated Q-switches, one each to a cavity, said pulses having unique pulse spacings set by said sequential actuation; and

means for detecting electromagnetic radiation from said target having said unique pulse spacings.

4. A method for designating a target comprising the steps of:

illuminating a target with multiple laser pulses of differing colors from a single rod, multiple cavity laser source, said pulses having pulse spacings and colors unique to said source; and

detecting electromagnetic radiation from said target having said unique pulse spacings and colors, thereby providing countermeasure resistance in terms of the difficulty of detecting and duplicating said colors and spacings.

5. The method of claim 4 and further including the step of providing that the interpulse spacings are small enough such that the multiple pulse nature is difficult to detect for those not initially aware of the multi-pulse nature of the illumination.

6. A method of designating a target comprising:

illuminating a target with multiple laser pulses of different colors, said pulses having pulse spacings unique to a known illuminating means and selectably variable down to a predetermined small spacing by virtue of the use of differing colors, whereby the small pulse spacings, the variability of the pulse spacings, and the use of two colors makes detection of the multiple pulse nature of the illumination difficult to detect by the target and duplication of the exact interpulse spacing by the target difficult.

7. A method for designating a target comprising illuminating a target from a single rod, multiple cavity laser with multiple laser pulses of differing colors, said pulses having pulse spacings unique to an illuminating means, whereby electromagnetic radiation reflected by said target having said unique pulse spacings designates the target as the one illuminated by said illuminating means.