Penn State Electro Optics Center

State College, PA, United States

Penn State Electro Optics Center

State College, PA, United States
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Einsporn J.A.,Penn State Electro Optics Center | Zhou A.F.,Indiana University of Pennsylvania
Physics Teacher | Year: 2011

Going "green" is a slogan that is very contemporary, both with industry and in the political arena. Choosing more energy-efficient devices is one way homeowners can "go green." A simple method is to change home lighting from hot incandescent bulbs to compact fluorescent lights (CFLs). But do they really save energy? How do their illuminations compare? Even if the CFLs are more energy efficient, they still add to our pollution problem because of the mercury inside them. Light-emitting diodes (LEDs) could be the answer, but they are not available at our local stores. Can LEDs be made to screw right into a standard socket? How expensive are they? What are the power consumptions of so-called "60-W" and "100-W" CFL and LED light bulbs? These are the questions that are answered during this lab activity. Students measure the voltage and current for each of the three types of bulbs, and then calculate the electrical power required by each. An optional experiment is to set the light outputs of each bulb so they are equal in intensity, and then determine the power consumed. While not practical in the home, this experiment gives students an understanding of value for their buck.

Farrell S.,George Mason University | Rao M.V.,George Mason University | Brill G.,U.S. Army | Chen Y.,U.S. Army | And 4 more authors.
Journal of Electronic Materials | Year: 2011

In our previous study of ex situ thermal cycle annealing (TCA) of molecular beam epitaxy (MBE)-grown mercury cadmium telluride (HgCdTe) on CdTe/Si(211) composite substrates we showed consistent dislocation density reduction to ~1 × 10 6 cm -2. In this work, we have extended our study to understand the effects of TCA at lower temperatures and fewer cycles than studied previously. By examining TCA performed at the lower end of the temperature spectrum (as low as 385°C), we are able to show an exponential correlation between etch pit density (EPD) and temperature. Varying the number of cycles also shows a similar exponential correlation with EPD. These results suggest that these are the two major factors driving dislocation annihilation and/or coalescence. In this paper, we discuss the theoretical mechanism behind dislocation reduction, both at the surface and throughout the bulk of the HgCdTe layer. © 2011 TMS.

Farrell S.,George Mason University | Rao M.V.,George Mason University | Brill G.,U.S. Army | Chen Y.,U.S. Army | And 4 more authors.
Journal of Electronic Materials | Year: 2013

The morphology and classification of etch pits in molecular beam epitaxy-grown (211) HgCdTe/CdTe/Si layers were investigated using the Schaake and Benson etch pit density (EPD) etches. The two EPD etches were compared and shown to have a 1:1 correlation in the etch pits that were produced. Close examination of the shape of the etch pits via scanning electron microscopy shows that several distinguishable classifications of etch pits are revealed using both etches. Samples subjected to thermal cycle annealing (TCA) treatment show a nonuniform reduction in etch pit populations according to the classification defined in this study. In particular, a class of etch pits called "fish shaped" are completely absent after TCA and can account for up to one-third of the total reduction in EPD. © 2013 TMS (outside the USA).

Farrell S.,George Mason University | Brill G.,U.S. Army | Chen Y.,U.S. Army | Wijewarnasuriya P.S.,U.S. Army | And 3 more authors.
Journal of Electronic Materials | Year: 2010

We present the results of ex situ thermal cycle annealing (TCA) of molecular beam epitaxy grown mercury cadmium telluride (HgCdTe) on Cd(Se)Te/Si(211) composite substrates. We examined the variation in the etch pit density (EPD) and overall crystalline quality with respect to annealing temperature, number of annealing cycles, total annealing time, pre-annealed EPD/crystal quality, buffer layer quality, and buffer layer lattice constant. Using TCA we observed an order of magnitude reduction in the dislocation density of the HgCdTe layers and a corresponding decrease in x-ray full width at half maximum, when the as-grown layer EPD was on the order of 1 × 10 7 cm -2. Among all the parameters studied, the one with the greatest influence on reducing EPD was the number of annealing cycles. We also noticed a saturation point where the HgCdTe/Si EPD did not decrease below ∼1 × 10 6 cm -2, regardless of further TCA treatment or the as-grown EPD value. © 2009 TMS.

Mazurowski J.,Penn State Electro Optics Center | Habiby S.F.,Applied Communication science
AIAA/IEEE Digital Avionics Systems Conference - Proceedings | Year: 2013

This paper describes the use and value of digital Wavelength Division Multiplexed (WDM) networks on-board small avionic and space platforms. Packaging and heat transfer efficiency are achieved when all of the optical wavelength sources occupy a common location. Each receiver is allocated a specific addressable wavelength that can be selected or tuned at the source (transmitter). Individual delays may be applied to assure synchronization at each receiver. The output of each individual source wavelength is pre-modulated with a clock signal. Signal modulation is applied by passing or rejecting the clock signals. Control plane functions can be merged with the data plane functions. Although based on a single data rate, this implementation of the digital WDM LAN concept can possibly be extended to process packet and analog payloads. © 2013 IEEE.

Mazurowski J.,Penn State Electro Optics Center | Habiby S.F.,Penn State Electro Optics Center
2014 IEEE Avionics, Fiber-Optics and Photonics Technology Conference, AVFOP 2014 | Year: 2014

We describe a digital Wavelength Division Multiplexed (WDM) architecture for small platforms that emphasizes energy efficiency and deterministic behavior. Heat transfer efficiency is improved as the co-located optical wavelength sources are pre-modulated with clock signals. © 2014 IEEE.

Brickeen B.K.,Penn State Electro Optics Center | Shanta C.,Penn State Electro Optics Center
Optical Engineering | Year: 2010

The influences of thermo-chemical reduction processing on the physical properties of lithium niobate are studied. The behavior of the surface resistivity and the induced optical absorption are characterized, with trends indicating a significant reduction in resistivity can be realized before absorption becomes problematic in the 1.0 m spectral region. The edge localization of the effects in bulk materials is identified, suggesting a central clear aperture of high transmission is possible even when large absorption near the crystal edges is observed. Electro-optical Q-switch crystals were processed with varying degrees of annealing and reduction, leading to the realization of several samples with optimal combinations of modified surface and bulk properties. The highest transmission samples were then tested under transient ambient temperature conditions and compared to unprocessed crystals. The processed samples showed a significant reduction in the transient depolarization of transmitted laser light due to the pyroelectric effect. © 2010 Society of Photo-Optical Instrumentation Engineers.

Dey D.,Carnegie Mellon University | Geyer C.,iRobot | Singh S.,Carnegie Mellon University | Digioia M.,Penn State Electro Optics Center
International Journal of Robotics Research | Year: 2011

Unmanned Aerial Vehicles (UAVs) have played vital roles recently in both military and non-military applications. Oneof the reasons UAVs today are unable to routinely fly in US National Airspace (NAS) is because they lack the senseand ability to avoid other aircraft. Although certificates of authorization can be obtained for short-term use, it entailssignificant delays and bureaucratic hurdles. Therefore, there is a great need to develop a sensing system that is equivalent to or has greater performance than a human pilot operating under Visual Flight Rules (VFR). This is challengingbecause of the need to detect aircraft out to at least 3 statute miles, while doing so on field-of-regard as large as30°( vertical) × 220°( horizontal) and within the payload constraints of a medium-sized UAV. In this paper we report on recent progress towards the development of a field deployable sense-and-avoid system and concentrate on the detectionand tracking aspect of the system. We tested a number of approaches and chose a cascaded approach that resulted in100% detection rate (over about 40 approaches) and 98% tracking rate out to 5 statute miles and a false positive rate of 1every 50 frames. Within a range of 3.75 miles we can achieve nearly 100% tracking rate. © SAGE Publications 2011.

Campbell B.R.,Penn State Electro Optics Center | Forster L.A.,Penn State Electro Optics Center | Bernot D.M.,Penn State Electro Optics Center
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

Lasers can uniquely be used to create physical changes inside a bulk material. Traditional manufacturing processes are limited to surface modifications, but a laser can be focused at any location inside a material transparent to that wavelength. Using sub surface machining methods with ultrashort pulse lasers two practical applications are demonstrated. First, a laser is used to sever short-circuited wires embedded deep inside a thick piece of glass, effectively repairing a defective wire network. Second, subsurface bar-coding was shown to produce readable markings. Surface laser markings were shown to weaken the glass, but subsurface marking had virtually no effect on strength.

Mazurowski J.,Penn State Electro Optics Center
2011 IEEE Avionics, Fiber- Optics and Photonics Technology Conference, AVFOP 2011 | Year: 2011

Understanding complete behavior of a system during testing may require many- perhaps hundreds- of sensors. Wavelength division multiplexing using single mode fiber can help simplify this. Three decisions assist with the selection of connection methods. © 2011 IEEE.

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