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Summary
Accurate characterization of optoelectronic equipment is important to applications such as communications, medicine, semiconductor manufacturing, as well as laser safety. This project focuses on measurements of critical laser parameters, especially laser power and energy. Project staff participate in national and international standards committees for laser safety and optoelectronic devices. Through research into new optical materials and detectors, the Optoelectronics Division has extended and improved measurements of lasers and optical detectors, including development of low-noise, spectrally flat, highly uniform optical detectors; high-accuracy transfer standards for optical-fiber and laser power measurements; and advanced laser systems for laser power and energy measurements.
Description
Meeting the current and future needs of the laser and optoelectronics industries requires investigation and development of improved measurement methods and instrumentation for high-accuracy laser metrology over a wide range of powers, energies, and wavelengths. The Optoelectronics Division has historically used electrically calibrated laser calorimeters to provide traceability to the SI units for laser power and energy. The Division has also developed measurement capabilities based on a Laser Optimized Cryogenic Radiometer, which provides an order of magnitude in accuracy improvement for laser power measurements, compared to electrically calibrated radiometers.
With few exceptions, all of the primary
measurement standards for establishing traceability to fundamental units for radiometry are based on thermal detectors. Research into optical coatings has led to superior thermal detectors with absorber coatings consisting of purified carbon nanotubes. To support advanced carbon nanotube coatings, project staff have developed a set of characterization tools for practical measurements of bulk nanomaterials using non-contact probes pioneered at NIST. Existing measurement tools are neither practical nor useful for current and future large-scale production of nanomaterials. These tools often rely on physical contact between the test probe and the material under study. However, physical contact between probes and nanomaterials may alter the material property of interest; for example differentiating bulk resistance from contact resistance. Advanced, cost effective analytical techniques are needed so that manufacturers, product developers, and regulatory agencies can truly "see" what they have. Photons, being massless and chargeless, are an ideal, non-contact probe. These non-contact techniques, relying on photon-matter interactions, include resonant-coupled photoconductive decay, high-Q dielectric measurements, absorption spectroscopy, and fluorescence.
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