Photonics/Optics

DisplayPort Technology — Heir Apparent to VGA?

For the last 20 years we have connected our monitors to our computer systems having the confidence that upon turn-on, we could surf or create with never a consideration of whether the display would operate satisfactorily. VGA (Video Graphics Adaptor) technology enabled us to do that with CRTs as well as with flat panel displays. Now, however, the viewing benchmarks are being reset, as are system design considerations. There’s a new interface on the horizon called DisplayPort!

Posted in: Application Briefs, Applications, ptb catchall, Photonics

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Optoelectronic System Measures Distances to Multiple Targets

This system operates at an update rate >10 Hz. NASA’s Jet Propulsion Laboratory, Pasadena, California An optoelectronic metrology apparatus now at the laboratory-prototype stage of development is intended to repeatedly determine distances of as much as several hundred meters, at submillimeter accuracy, to multiple targets in rapid succession. The underlying concept of optoelectronic apparatuses that can measure distances to targets is not new; such apparatuses are commonly used in general surveying and machining. However, until now such apparatuses have been, variously, constrained to (1) a single target or (2) multiple targets with a low update rate and a requirement for some a priori knowledge of target geometry. When fully developed, the present apparatus would enable measurement of distances to more than 50 targets at an update rate >10 Hz, without a requirement for a priori knowledge of target geometry.

Posted in: Photonics, Briefs, ptb catchall, Tech Briefs, Photonics

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Large Solar-Rejection Filter

This lightweight filter comprises a multilayer spectral coating on a flexible membrane. NASA’s Jet Propulsion Laboratory, Pasadena, California An optical filter consisting of a multilayer spectral coating on a flexible membrane has been designed to be placed in front of the 200-in. (5.08-m) Hale telescope on Mt. Palomar. The filter is intended to protect the telescope against solar radiant flux and limit solar heating of the interior of the telescope dome while transmitting light at the 1,064-nm wavelength of the Mars Laser Communication Demonstration.

Posted in: Photonics, Briefs, ptb catchall, Tech Briefs, Photonics

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Large Solar-Rejection Filter

This lightweight filter comprises a multilayer spectral coating on a flexible membrane. An optical filter consisting of a multilayer spectral coating on a flexible membrane has been designed to be placed in front of the 200-in. (5.08-m) Hale telescope on Mt. Palomar. The filter is intended to protect the telescope against solar radiant flux and limit solar heating of the interior of the telescope dome while transmitting light at the 1,064-nm wavelength of the Mars Laser Communication Demonstration.

Posted in: Photonics, Briefs, ptb catchall, Tech Briefs, Photonics

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LED-Equipped Spectrophotometers Find Their Way to the Factory Floor

Companies that manufacture products ultimately used by consumers — interior trim for cars, vinyl siding for homes, decorative stone for landscaping, interior wall paints, etc. — are often discovering that they need to use precise spectrophotometers to ensure first-time color quality and lotto-lot consistency.

Posted in: Articles, Features, ptb catchall, Photonics

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Improving Lens Performance With Transmitted Wavefront Error Testing

During design and manufacturing, optical systems and lenses are toleranced and tested to ensure the smallest possible performance error. Matching most optics manufacturing companies’ capabilities, lenses are traditionally toleranced with individual surface specifications — surface power and irregularity, or form, error. These tolerances and the associated tests control performance of a single surface, not the entire lens. Because lens designs are built around transmission characteristics such as spot size and RMS wavefront error, the performance of the entire lens, not the individual surfaces, is the true target. Transmitted wavefront error (TWE), which is the error in transmission of light through a lens, is the true target. For aspheric surfaces, traditional single-surface, three-dimensional surface form metrology is not easy. Aside from testing the true target, it may be easier and faster to make use of TWE for aspheric lenses. Using innovative metrology and developing a feed-forward manufacturing strategy, tolerancing and testing TWE can reduce risk in optical designs, improve performance and reduce cost and lead time.

Posted in: Application Briefs, Applications, ptb catchall, Photonics

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Optical Magnetometer Incorporating Photonic Crystals

Sensitivity would be increased by orders of magnitude. NASA’s Jet Propulsion Laboratory, Pasadena, California According to a proposal, photonic crystals would be used to greatly increase the sensitivities of optical magnetometers that are already regarded as ultrasensitive. The proposal applies, more specifically, to a state-of-the-art type of quantum coherent magnetometer that exploits the electromagnetically-induced-transparency (EIT) method for determining a small change in a magnetic field indirectly via measurement of the shift, induced by that change, in the hyperfine levels of resonant atoms exposed to the field.

Posted in: Photonics, Briefs, ptb catchall, Tech Briefs, Photonics

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