Special Coverage

Soft Robot “Walks” on Any Terrain
Defense Advanced Research Projects Agency
Using Microwaves to Produce High-Quality Graphene
Transducer-Actuator Systems for On-Machine Measurements and Automatic Part Alignment
Wide-Area Surveillance Using HD LWIR Uncooled Sensors
Heavy Lift Wing in Ground (WIG) Cargo Flying Boat
Technique Provides Security for Multi-Robot Systems
Bringing New Vision to Laser Material Processing Systems
NASA Tests Lasers’ Ability to Transmit Data from Space
Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines

Photon Counting Using Edge-Detection Algorithm

Improved optical communications links can be used in building-to-building networks in high-attenuation conditions such as rain or fog.

New applications such as high-data-rate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with sub-nanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to over-count the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA).

Posted in: Briefs, Physical Sciences, Mathematical models, Communication protocols, Integrated circuits, Optics, Communication protocols, Integrated circuits, Optics
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Optical Structural Health Monitoring Device

This non-destructive, optical fatigue detection and monitoring system relies on a small and unobtrusive light-scattering sensor that is installed on a component at the beginning of its life in order to periodically scan the component in situ. The method involves using a laser beam to scan the surface of the monitored component. The device scans a laser spot over a metal surface to which it is attached. As the laser beam scans the surface, disruptions in the surface cause increases in scattered light intensity. As the disruptions in the surface grow, they will cause the light to scatter more. Over time, the scattering intensities over the scanned line can be compared to detect changes in the metal surface to find cracks, crack precursors, or corrosion. This periodic monitoring of the surface can be used to indicate the degree of fatigue damage on a component and allow one to predict the remaining life and/or incipient mechanical failure of the monitored component.

Posted in: Briefs, Physical Sciences, Aircraft structures, Lasers, Sensors and actuators, Lasers, Sensors and actuators, Fatigue, Non-destructive tests
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Cooling Lasers with Thin-Film Thermoelectric Coolers

Laser diodes for telecommunications have traditionally used thermoelectric coolers (TECs) for precision temperature control to improve diode output levels and maintain wavelength integrity. A major trend for photonics in telecommunications has been the move to more integrated packaging that is smaller and simpler in structure in order to lower costs. This, in turn, has opened the door for higher volume manufacturing. In the course of this transition, conventional TEC solutions have become increasingly difficult to implement as conventional bulk thermoelectric technology has not kept pace with the size and power density requirements for next generation devices.

Posted in: Features, ptb catchall, Articles, Photonics, Lasers, Telecommunications, Lasers, Telecommunications, Thermal management, Thermal management, Packaging
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Tunable Bandpass Filters

The ubiquitous techniques of fluorescence and Raman imaging and spectroscopy rely heavily on spectrally precise, high-quality and high-throughput optical filter technologies. As both fluorescence and Raman-based techniques move from traditional R&D-based environments into medical and clinical (diagnostic) settings, even higher demands are placed on system performance. Therefore, it is necessary to continue to improve system components and architectures to meet the demanding challenges often encountered in biological applications.

Posted in: Applications, ptb catchall, Application Briefs, Photonics, Imaging, Imaging and visualization, Optics, Spectroscopy, Imaging, Imaging and visualization, Optics, Spectroscopy
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Holographic Vortex Coronagraph

This apparatus offers potential advantages of performance and manufacturability over conventional coronagraphs.

A holographic vortex coronagraph (HVC) has been proposed as an improvement over conventional coronagraphs for use in high-contrast astronomical imaging for detecting planets, dust disks, and other broadband light scatterers in the vicinities of stars other than the Sun. Because such light scatterers are so faint relative to their parent stars, in order to be able to detect them, it is necessary to effect ultra-high-contrast (typically by a factor of the order of 1010) suppression of broadband light from the stars. Unfortunately, the performances of conventional coronagraphs are limited by low throughput, dispersion, and difficulty of satisfying challenging manufacturing requirements. The HVC concept offers the potential to overcome these limitations.

Posted in: ptb catchall, Tech Briefs, Briefs, Photonics, Imaging, Imaging and visualization, Imaging, Imaging and visualization, Performance upgrades, Noise, Noise, Visibility
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Photon Counting Using Edge-Detection Algorithm

Improved optical communications links can be used in building-to-building networks in high-attenuation conditions such as rain or fog.

New applications such as high-data-rate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with sub-nanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to over-count the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA).

Posted in: ptb catchall, Tech Briefs, Briefs, Photonics, Mathematical models, Fiber optics, Integrated circuits, Fiber optics, Integrated circuits
Read More >>

Optical Structural Health Monitoring Device

This device detects microscopic cracks and surface structural changes in components.

This non-destructive, optical fatigue detection and monitoring system relies on a small and unobtrusive light-scattering sensor that is installed on a component at the beginning of its life in order to periodically scan the component in situ. The method involves using a laser beam to scan the surface of the monitored component. The device scans a laser spot over a metal surface to which it is attached. As the laser beam scans the surface, disruptions in the surface cause increases in scattered light intensity. As the disruptions in the surface grow, they will cause the light to scatter more. Over time, the scattering intensities over the scanned line can be compared to detect changes in the metal surface to find cracks, crack precursors, or corrosion. This periodic monitoring of the surface can be used to indicate the degree of fatigue damage on a component and allow one to predict the remaining life and/or incipient mechanical failure of the monitored component.

Posted in: ptb catchall, Tech Briefs, Briefs, Photonics, Optics, Sensors and actuators, Optics, Sensors and actuators, Vehicle health management
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Product of the Month: Wireless MEMS Sensor for Glaucoma Diagnosis

STMicroelectronics (Geneva, Switzerland) has developed a wireless MEMS sensor that acts as a transducer, antenna, and mechanical support for the SENSIMED Triggerfish® continuous eye pressure monitor from Sensimed AG. The solution will enable better management of glaucoma patients via earlier diagnosis and treatment that is tailored to each patient. The solution is based on a “smart” contact lens that uses a tiny embedded strain gauge to monitor the curvature of the eye over a period of 24 hours, providing disease management data that is not obtainable using conventional ophthalmic equipment. The lens also contains an antenna, a tiny dedicated processing circuit, and an RF transmitter that communicate the measurements to a receiver worn around the patient's neck. Because it is powered via the received radio waves, it does not need to be connected to a battery.

Posted in: Products, Products
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Vibration Cancellation System

Technical Manufacturing Corporation (Peabody, MA) has introduced the STACIS® iX LaserTable-Base™, a hybrid piezoelectric/ air active vibration cancellation system for optical tables. TMC’s patented STACIS technology incorporates piezoelectric actuators and inertial vibration sensors to cancel vibration at very low frequencies (1 to 3 Hz) for applications such as interferometry, single- and multiphoton microscopy, and scanning probe microscopy.

Posted in: Products, Products
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VCSEL Chips

The Optoelectronics Company (Hertfordshire, UK) has introduced its SH85-4U001, 850nm VCSEL chips with a maximum output power of 20mW at an operating current of 50mA and operating voltage of 2.1V maximum. The chips feature a spectral bandwidth (RMS) of 0.85nm maximum and threshold current of 15mA typical.

Posted in: Products, Products
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