Lockheed Idaho Technologies Company, P.O. Box 1625, Idaho Falls, ID 83415-3521

A -- PIEZOELECTRIC MEASUREMENT OF LASER POWER (IDR 191) SOL Cbd112 DUE 112398 POC Paul Grahovac WEB: Idaho National Engineering & Environmental Laboratory, http://www.inel.gov/procurement/litco/index.html. E-MAIL: Paul Grahovac, pg2@inel.gov. A -- Piezoelectric Measurement of Laser Power (IDR 191), U. S. Patent Number 5,048,969. Contact Mr. Paul Grahovac. Potential technology development and licensing opportunity with Lockheed Martin Idaho Technologies Company (LMITCO), the prime operating contractor for the Department of Energy at the Idaho National Engineering and Environmental Laboratory (INEEL). LMITCO is seeking a written indication of interest from industry partners interested in funding a collaborative technology development project and or entering into a license agreement for the purpose of developing and commercializing this technology. License terms will include an up-front licensing fee and a running royalty based on a percentage of sales. A description of the technology follows. LMITCO has patented the following technology (U. S. Patent Number 5,048,969). ABSTRACT: A method for measuring the energy of individual laser pulses or a series of laser pulses by reading the output of a piezoelectric (PZ) transducer which has received a known fraction of the total laser pulse beam. An apparatus is disclosed that reduces the incident energy on the PZ transducer by means of a beam splitter placed in the beam of the laser pulses. BACKGROUND OF THE INVENTION: This invention relates to the use of a piezoelectric (PZ) transducer as a method of measuring the energy of a pulsed laser and an apparatus that can measure this energy. Conventional power and energy meters, for high power pulsed lasers include various thermal and electro-optic devices designed to convert all or part of the pulse energy into thermal or electrical energy. A typical high power laser power meter will consist of a thermopile (a device utilizing thermocouples for converting thermal energy into electrical energy) and a device for monitoring the electrical output of the thermopile where it is absorbed and causes a temperature increase in the material of the thermopile. As the temperature rises, the array of thermocouples generate an electric potential which is sensed by somesort of voltage metering device. The length of time for such systems to come to equilibrium after the introduction of the laser beam is typically quite long (perhaps minutes). By introducing a series of pulses from a pulsed laser, the energy of the pulses may be integrated to produce a total energy for the entire sequence of pulses. The individual pulse is inferred by dividing the total energy measured by the number of pulses. However, such measurement assumes equal pulse energy, which may or may not be valid. Finally, such measurement devices typically encounter relatively severe problems with "drift" in the laser output caused by environmental temperature variations, instabilities in the laser control electronics or other effects, all of which are exacerbated by the relatively slow response time of the devices. More sophisticated devices such as photodiodes, which measure laser power directly by impinging the laser beam on the measuring device, are prone to damage, especially when impacted with a beam froma high power laser. A particularly vexing problem arises in the measurement of the energy of a rapidly pulsed laser, especially when large energies or power levels are involved. In such cases, one of two measurement approaches has conventionally been taken. Firstly, by monitoring the relative brightness of the successive pulses, while measuring the total energy in the pulse train with a thermal power meter, one can distribute the total measured energy among the various pulses based on the relative brightness of the pulses. Secondly, one can measure the brightness of the individual pulses using a conventional optical meter. The brightness is related to the pulse energy and is a measure of such energy. In using this method, all or part of the photons contained in the laser pulse fall on a detector material such as silicon or germanium, and their energy is converted into an electrical signal proportional to the number and energy of the photons. It should be noted that different detector materials must be used for different portions of the optical spectrum. Detector materials for visible radiation include silicon and germanium photodiodes, while for the infrared spectrum, materials such as HgCdTe, InSb, InGaAs, PbS and InAs, among others, have been used as photon detectors. Another class of photon detector are photomultiplier tubes (PMT), however, these have extreme sensitivity which generally precludes their use in high power measurements. Problems exist with each of these approaches, especially with higher pulse energies. In particular, the direct measurement of the brightness of laser pulses becomes very difficult due to the limited dynamic range of typical photon sensors. Additionally, small portions of the pulse must be separated (the beam must be "split") for measurement in a way that allows one to relate this partial energy back to the true total energy of the original pulse. Actual damage to the optical detector is a distinct possibility when energies exceed damage thresholds, as may happen when unknown pulses or pulses having large energy variations must be measured. This is not an opportunity to provide goods or services to LMITCO or the Department of Energy. This Request for Interest (RFI) will close to response 30 days after publication. Interested parties should send a description of their company and their ability to commercialize this technology to the address below. Paul Grahovac, Account Executive, Technology Transfer Office, LMITCO, P. O. Box 1625, Idaho Falls, ID 83415-3805. E-mail is pg2@inel.gov. Posted 10/20/98 (W-SN263660). (0293)

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