Photonics/Optics

Computer-Assisted Laser Treatment Using Real-Time Retinal Tracking

This computerized system accurately guides laser shots to diseased retinal areas. Diabetic retinopathy resulting from long-term diabetes mellitus is one of the common diseases that leads to choroidal neovascularization (CNV), a leading cause of blindness. Among the currently available treatment methods, a laser can be used to photocoagulate the diseased areas. Several thousand laser shots are usually required during such treatment. Special care must be taken to avoid hitting the blood vessel tree, the macula, the optic disk, and the region among them. For a single eye, this procedure requires up to several hours that are usually divided over many treatment sessions. Consequently, the development of an accurate laser treatment guidance system to treat the whole retina in one session would improve the effectiveness of such procedures.

Posted in: Bio-Medical, Briefs, TSP, Briefs, TSP, Lasers & Laser Systems, Photonics

Read More >>

Disk Lasers in the Photovoltaic Industry

Diverse types of lasers, such as nanosecond, pulsed, and excimer, have been considered for various applications in the photovoltaic industry, including edge isolation, edge deletion, drilling for back contact, cutting of Si-wafer, and patterning of crystalline solar cells. High power lasers, with high stability and high efficiency in addition to high beam quality, are needed now more than ever.

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

Read More >>

Wafer Level Camera Technology

Film cameras were traditionally manufactured by discrete assembly, which means each component was fabricated as an individual item, tested if necessary, and then assembled into the final working product. The advent of solid state imaging did little to change this approach. The film was merely replaced by a light-sensitive electronic component. The only significant change was that the mechanical shutter was rendered obsolete and its action generated electronically within the imager die.

Posted in: Articles, Features, ptb catchall, Photonics

Read More >>

Measuring the Color and Appearance of Special-Effect Paint

Manufacturers that design, formulate and apply coatings have struggled for years to find a rigorous and easy-to-use method that reliably measures the color and appearance of special-effect paints. Companies tried to relate measurements taken with handheld spectrophotometers that collect colorimetric data from several in-plane angles to events that occurred in production processes, but these instruments, by their nature, could not collect the essential data points to yield reliable results. Other companies have tried to skirt the problem by creating a coarseness index or “sparkle” metric that relies on photographic images taken in-plane, but this method is easily confused and insufficient for rigorous analysis.

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

Read More >>

Integrated Miniature Arrays of Optical Biomolecule Detectors

Many biochemical species could be detected simultaneously. NASA’s Jet Propulsion Laboratory, Pasadena, California Integrated miniature planar arrays of optical sensors for detecting specific bio-chemicals in extremely small quantities have been proposed. An array of this type would have an area of about 1 cm2. Each element of the array would include an optical microresonator that would have a high value of the resonance quality factor (Q ≈ 107). The surface of each microresonator would be derivatized to make it bind molecules of a species of interest, and such binding would introduce a measurable change in the optical properties of the microresonator. Because each microresonator could be derivatized for detection of a specific biochemical different from those of the other microresonators, it would be possible to detect multiple specific biochemicals by simultaneous or sequential interrogation of all the elements in the array. Moreover, the derivatization would make it unnecessary to prepare samples by chemical tagging.

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

Read More >>

Inter-Symbol Guard Time for Synchronizing Optical PPM

This method would involve less computation than does the pilot-symbol method. NASA’s Jet Propulsion Laboratory, Pasadena, California An inter-symbol guard time has been proposed as a means of synchronizing the symbol and slot clocks of an optical pulse-position modulation (PPM) receiver with the symbol and slot periods of an incoming optical PPM signal. (Such synchronization is necessary for correct identification of received symbols.) The proposal is applicable to the low-flux case in which the receiver photodetector operates in a photon-counting mode and the count can include contributions from incidental light sources and dark current. The use of the inter-symbol guard time would be an alternative to a prior synchronization method based on the periodic transmission of a fixed pilot symbol.

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

Read More >>

Treating Retinal Disease with FPGA Controlled Lasers

More than 50 percent of Americans diagnosed with diabetes are at risk of developing diabetic retinopathy, a retinal disease that can lead to blindness. The condition is a result of diabetes affecting the circulatory system of the retina and causing abnormal new blood vessel growth. It has become the leading cause of new blindness among U.S. adults.

Posted in: Articles, Features, ptb catchall, Photonics

Read More >>