Photonics

Tactile Feedback for Touch-input Devices

As products become more featurerich, manufacturers are looking at ways to improve the human-computer interface (HCI). Touchscreens, with intuitive operation and software flexibility, and screen-printed touch surfaces, with refined aesthetics and better sealing, have become extremely popular. But what these touch-input devices do not supply is tactile confirmation of (1) a button’s location and (2) pressing it. The loss of this tactile information can be detrimental to user engagement and understanding, productivity, completion of transactions, safety, and satisfaction. In some applications, the lack of tactile feedback has been enough of a problem to prevent the conversion from mechanical switches to digital controls. The solution is simple — add tactile feedback to secure the best features of touch-input devices.

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

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Phase Matching of Diverse Modes in a WGM Resonator

Phase matching is necessary for exploitation of nonlinear optical phenomena. NASA’s Jet Propulsion Laboratory, Pasadena, California Phase matching of diverse electromagnetic modes (specifically, coexisting optical and microwave modes) in a whispering-gallery-mode (WGM) resonator has been predicted theoretically and verified experimentally. Such phase matching is necessary for storage of microwave/terahertz and optical electromagnetic energy in the same resonator, as needed for exploitation of nonlinear optical phenomena.

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

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Microwave-to-Optical Conversion in WGM Resonators

Three-wave mixing, resonance, and low loss would result in high efficiency. NASA’s Jet Propulsion Laboratory, Pasadena, California Microwave-to-optical frequency converters based on whispering-gallery-mode (WGM) resonators have been proposed as mixers for the input ends of microwave receivers in which, downstream of the input ends, signals would be processed photonically. A frequency converter as proposed (see figure) would exploit the nonlinearity of the electromagnetic response of a WGM resonator made of LiNbO3 or another suitable ferroelectric material. Up-conversion would take place by three-wave mixing in the resonator.

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

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Wide-Band Microwave Receivers Using Photonic Processing

One receiver would have the functionality of multiple traditional heterodyne microwave receivers. NASA’s Jet Propulsion Laboratory, Pasadena, California In wide-band microwave receivers of a type now undergoing development, the incoming microwave signals are electronically preamplified, then frequency-up-converted to optical signals that are processed photonically before being detected. This approach differs from the traditional approach, in which incoming microwave signals are processed by purely electronic means. As used here, “wide-band microwave receivers” refers especially to receivers capable of reception at any frequency throughout the range from about 90 to about 300 GHz. The advantage expected to be gained by following the up-conversion-and-photonic-processing approach is the ability to overcome the limitations of currently available detectors and tunable local oscillators in the frequency range of interest.

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

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WGM Resonators for Terahertz-to-Optical Frequency Conversion

Receivers containing these devices are contemplated for astronomical and military uses. NASA’s Jet Propulsion Laboratory, Pasadena, California Progress has been made toward solving some practical problems in the implementation of terahertz-to-optical frequency converters utilizing whispering-gallery-mode (WGM) resonators. Such frequency converters are expected to be essential parts of non-cryogenic terahertz-radiation receivers that are, variously, under development or contemplated for a variety of applications in airborne and spaceborne instrumentation for astronomical and military uses.

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

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Temperature Sensors Based on WGM Optical Resonators

Differences between temperature-dependent frequencies of resonances would be measured. NASA’s Jet Propulsion Laboratory, Pasadena, California A proposed technique for measuring temperature would exploit differences between the temperature dependences of the frequencies of two different electromagnetic modes of a whispering-gallery-mode (WGM) optical resonator. An apparatus based on this technique was originally intended to be part of a control system for stabilizing a laser frequency in the face of temperature fluctuations. When suitably calibrated, apparatuses based on this technique could also serve as precise temperature sensors for purposes other than stabilization of lasers.

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

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Four-Pass Coupler for Laser-Diode-Pumped Solid-State Laser

A smaller laser slab can be made to perform comparably to a larger one. Goddard Space Flight Center, Greenbelt, Maryland A four-pass optical coupler affords increased (in comparison with related prior two-pass optical couplers) utilization of light generated by a laser diode in side pumping of a solid-state laser slab. The original application for which this coupler was conceived involves a neodymium-doped yttrium aluminum garnet (Nd:YAG) crystal slab, which, when pumped by a row of laser diodes at a wavelength of 809 nm, lases at a wavelength of 1,064 nm.

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

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