Objective
The National Aeronautics and Space Administration (NASA) seeks to transfer an innovative Holographic Circle to Point Converter to commercial applications. Originally developed at NASA Goddard Space Flight Center, this holographic optical element resolves the circular fringe patterns generated by a Fabry-Perot interferometer into focused points. These points can be focused onto solid-state detectors, such as those used in Doppler lidar systems. Goddards holographic circle-to-point converter can reduce the cost, size, and complexity of Doppler and other lidar systems where either separating or combining light wavelengths is necessary. Figure 1 Holographic Plate Imaging a Fabry-Perot Fringe Pattern
Description
A Doppler lidar system must resolve the circular fringe patterns generated by a Fabry-Perot interferometer. These circular patterns are typically the useful end result of the back-scattered laser light source that returns to the instrument. Unfortunately, most circular detectors used to resolve these patterns have low quantum efficiency and require cooling supplies.Researchers at NASA Goddard Space Flight Center have developed a new holographic circle-to-point converter that resolves the circular patterns into focused points. These points can be focused onto solid-state detectors. The points may be focused into a single plane or even into a single line, allowing for the use of certain linear detectors.The technology consists of a holographic plate of concentric ring zones, or annuli. The plate size and number of annuli can vary to fit the instrument and the measuring requirements. Each annulus focuses a wavelength component of the fringe light into a single point. The intensity of the individual points can be independently measured using commercially available detectors. Figure 2 Holographic Plate Imaging An Incident Plane WaveNASAs circle-to-point converter overcomes the limitations of circular photomultiplier-type detectors. The technology does not require high voltages or a cooling system, and it is easily manufactured using standard holographic techniques. The Ralcon Corporation produced the first successful prototypes of Goddards technology in 1996, with performance meeting expectations. Doppler lidar systems that use this technology can be less expensive, less complex, and smaller than traditional Doppler lidar systems, creating opportunities for a variety of commercial applications.The inventors of this technology also are investigating a concept that uses the converter in reverse to combine, rather than divide, incident light. This concept could work for inputs of equal or different wavelengths. It would allow an efficient means for combining several input light beams into one common beam, which might be useful in diode pumping of laser rods or wavelength division multiplexing for fiber optic transmissions.
Benefits
- Flexible: The technology can produce a variable number of points, which can be focused into a single plane or a single line.
- Lightweight: The converter allows for smaller, lighter optical systems.
- Low power: The technology does not require high voltages.
- Self-cooling: No cooling systems are required.
- Low cost: The converter is less expensive than other devices that perform the same function.
- Manufacturable: The device is easily manufactured using standard holographic techniques.
Potential Application(s)
- Ground-based Doppler lidar
- Satellite-based Doppler lidar
- Portable wind measurement systems
- Turbulence detection for airports/aircraft
- Tracking airborne particles
- Data storage
- Multispectral measurement systems
- Multifield-of-view telescopes
- Research
- Diode pumping of laser rods
- Wavelength division multiplexing
Technology Commercialization Status
This device is part of NASAs technology transfer program. The program seeks to stimulate commercial use of NASA-developed technology. A patent application for the technology has been filed. NASA invites commercial companies to consider licensing this technology for commercial applications. NASA is flexible in its partnering arrangements, and opportunities exist for exclusive, partially exclusive, and nonexclusive licenses.
Related Web Sites
Related Technologies
Contact
If your company is interested in this technology please contact:
Office Of Technology Transfer
GSFC
Phone: (301) 286-5810
FAX: (301) 286-0301
E-mail: Techtransfer@gsfc.nasa.gov
Public Release Date: 4/1/1999
Reference Number: TOP5-608
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