Apparatus and method for laser beam diagnosis
Abstract
An apparatus and method are disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam. 11 figures.
- Inventors:
- Issue Date:
- OSTI Identifier:
- 7027459
- Patent Number(s):
- 5042950
- Application Number:
- PPN: US 7-526757
- Assignee:
- Dept. of Energy, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- Resource Type:
- Patent
- Resource Relation:
- Patent File Date: 22 May 1990
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 42 ENGINEERING; LASER RADIATION; DIAGNOSTIC TECHNIQUES; BEAM MONITORING; COHERENT RADIATION; INTERFEROMETERS; MODULATION; REAL TIME SYSTEMS; ELECTROMAGNETIC RADIATION; MEASURING INSTRUMENTS; MONITORING; RADIATIONS; 426002* - Engineering- Lasers & Masers- (1990-)
Citation Formats
Salmon, Jr, J T. Apparatus and method for laser beam diagnosis. United States: N. p., 1991.
Web.
Salmon, Jr, J T. Apparatus and method for laser beam diagnosis. United States.
Salmon, Jr, J T. Tue .
"Apparatus and method for laser beam diagnosis". United States.
@article{osti_7027459,
title = {Apparatus and method for laser beam diagnosis},
author = {Salmon, Jr, J T},
abstractNote = {An apparatus and method are disclosed for accurate, real time monitoring of the wavefront curvature of a coherent laser beam. Knowing the curvature, it can be quickly determined whether the laser beam is collimated, or focusing (converging), or de-focusing (diverging). The apparatus includes a lateral interferometer for forming an interference pattern of the laser beam to be diagnosed. The interference pattern is imaged to a spatial light modulator (SLM), whose output is a coherent laser beam having an image of the interference pattern impressed on it. The SLM output is focused to obtain the far-field diffraction pattern. A video camera, such as CCD, monitors the far-field diffraction pattern, and provides an electrical output indicative of the shape of the far-field pattern. Specifically, the far-field pattern comprises a central lobe and side lobes, whose relative positions are indicative of the radius of curvature of the beam. The video camera's electrical output may be provided to a computer which analyzes the data to determine the wavefront curvature of the laser beam. 11 figures.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Tue Aug 27 00:00:00 EDT 1991},
month = {Tue Aug 27 00:00:00 EDT 1991}
}