Investigation of 10 sup 10 bit optical memory Interim report
Properties of Bragg holography in alkali halide crystals and application to optical data storage and processing
Bardos, A.↗
SEARCH · Engineering Papers
Results for “Optical applications”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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High-Q Microsphere Cavity for Laser Stabilization and Optoelectronic Microwave Oscillator
With submillimeter size and optical Q up to approximately 10 (exp 10), microspheres with whispering-gallery (WG) modes are attractive new component for fiber-optics/photonics applications and a potential core in ultra-compact high-spectral-purity optical and microwave oscillators. In addition to earlier demonstrated optical locking of diode laser to WG mode in a microsphere, we report on microsphere application in the microwave optoelectronic oscillator, OEO. In OEO, a steady-state microwave modulation of optical carrier is obtained in a closed loop including electro-optical modulator, fiber-optic delay, detector and microwave amplifier. OEO demonstrates exceptionally low phase noise (-140 dBc/Hz at l0kHz from approximately 10GHz carrier) with a fiber length approximately 2km. Current technology allows to put all parts of the OEO, except the fiber, on the same chip. Microspheres, with their demonstrated Q equivalent to a kilometer fiber storage, can replace fiber delays in a truly integrated device. We have obtained microwave oscillation in microsphere-based OEO at 5 to 18 GHz, with 1310nm and 1550nm optical carrier, in two configurations: 1) with external DFB pump laser, and 2) with a ring laser including microsphere and a fiber optic amplifier. Also reported is a simple and efficient fiber coupler for microspheres facilitating their integration with existing fiber optics devices.
Ilchenko, Vladimir S.↗
Ultra-high, resolution, modular optical angle encoder for space-based opto-mechanical applications
A 27-bit optical encoder using a novel patent pending technology has been developed by the MicroE Development Center of BEI Sensors & Systems Company and tested by the Sensor Systems Group (SSG) Inc., in a positioning and stabilization mirror assembly (PSMA) designed and constructed under a grant from the Marshall Space Flight Center. Test results verified performance within the specifications of the PSMA.
Luther, Holger↗
Non-mechanical optical path switching and its application to dual beam spectroscopy including gas filter correlation radiometry
A non-mechanical optical switch is developed for alternately switching a monochromatic or quasi-monochromatic light beam along two optical paths. A polarizer polarizes light into a single, e.g., vertical component which is then rapidly modulated into vertical and horizontal components by a polarization modulator. A polarization beam splitter then reflects one of these components along one path and transmits the other along the second path. In the specific application of gas filter correlation radiometry, one path is directed through a vacuum cell and one path is directed through a gas correlation cell containing a desired gas. Reflecting mirrors cause these two paths to intersect at a second polarization beam splitter which reflects one component and transmits the other to recombine them into a polarization modulated beam which can be detected by an appropriate single sensor.
Sachse, Glen W.↗
The applications of silicon liquid crystal light valves to optical data processing: A review
The applications of the photo-activated, the CCD-addressed, and the variable-grating mode liquid crystal light valves (LCLVs) to optical data processing are described. These applications include image correlation, level slicing, spectral analysis and correlation, bi-spectral image division, and matrix-matrix multiplication.
Efron, U.↗
Optical astronomy package feasibility study for Apollo applications program Executive summary report
Feasibility of adapting optical astronomy package to Apollo Application Program missions on lunar surface
ASTRONOMY↗
Calculations of the effect of roughness on microwave emissivity with application to the moon and Venus.
Roughness effect on microwave emissivity according to geometric optics with application to moon and Venus
Hetherington, N.↗
Electrostatic dust protection for optical elements
The application of electrostatic technology to the protection of optical components in earth-mounted and satellite orbital systems has been investigated. Theory and experiment indicate it is quite practical to prevent dust deposition in an earth environment. A mathematical analysis indicates even better results should be obtained in an orbital vehicle.
Hoenig, S. A.↗
On-Chip Single-Layer Integration of Diamond Spins with Microwave and Plasmonic Channels
On-chip scalable integration represents a major challenge for practical quantum devices. One particular challenge is to implement on-chip optical readout of spins in diamond. This readout requires simultaneous application of optical and microwave fields along with the efficient collection of fluorescence. These requirements are typically met using bulk optical components and dedicated microwave lines. Here, we experimentally demonstrate an on-chip integrated interface for diamond nitrogen vacancy (NV) spin-state preparation and readout, implemented in a planar single layer with only one patterning step. A nanodiamond with NV centers is positioned inside a v-groove waveguide milled in a thick gold film. The gold film carries the microwave control signal, while the v-groove acts as a fluorescence collector and, potentially, as an integrated pump filter. Hence, the device dimensions and fabrication complexity are substantially reduced. Our approach fosters further development of ultracompact nanoscale quantum sensors and quantum information processing devices on a monolithic platform.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Development of an Optical-Real Time Polarimetric Imaging System for Aerospace Applications
The design of an optical polarimetric imaging system, aimed to detect cracks or structural defects on the surface of rotating aircraft engine shafts, is presented. The experimental results have been processed by a real time wavelet denouncing system implemented by a Filed Programmable Gate Arrays (FPGA), which has been designed for this purpose. The experimental results clearly indicate that high signal-to-noise ratio signals can be obtained.
Giakos, George C.↗
Enhanced Laser Damage Threshold in Optically Addressable Light Valves via Aluminum Nitride Photoconductors
Abstract Optically addressable light valves (OALVs) are specialized optical components utilized for spatial beam shaping in various laser‐based applications, including optics damage mitigation, and enhanced functionality in diode‐based additive manufacturing requiring high intensities. Current state‐of‐the‐art OALVs employ photoconductors such as Bismuth Silicon Oxide (BSO) or Bismuth Germanium Oxide (BGO), which suffer from limited laser‐induced damage thresholds (LiDT) and inadequate thermal conductivities, thus restricting their use in high peak and average power applications. Aluminum nitride (AlN), an emerging ultra‐wide band gap (UWBG) III–V semiconductor, offers promising optoelectronic properties and superior thermal conductivity (>300 Wm −1 K −1 at 298° K, compared to BSO's 3.29 Wm −1 K −1 ). In this study, the first AlN‐based OALVs are designed, fabricated, and experimentally demonstrated using commercially available single‐crystal AlN substrates. These AlN‐based OALVs have shown clear superiority over BSO and BGO‐based devices. Design considerations for OALVs incorporating UWBG photoconductors are discussed, and the photoresponsivity from defect‐mediated sub‐bandgap absorption in AlN crystals is verified as sufficient for OALVs operating under high light fluences. The optimum driving voltage for the AlN‐based OALV is determined to be ≈ 45 V pp at 100 Hz, achieving a transmittance of 91.3%, an extinction ratio (ER) of more than 100, and a 51:1 image contrast.
36 MATERIALS SCIENCE↗
Optical technology for experiments and applications in cislunar space
Airborne lasers and telescopes for satellite studies on atmospheric properties and optical space communications
Plotkin, H. H.↗
Fiber optic sensors for military, industrial and commercial applications
Four examples of specific fiber optic sensor system designs, each of which demonstrates a different optical modulation format, are described. The birefrigent temperature transducer illustrates direct digital signal modulation. The temperature/pressure dependent semiconductor filter illustrates high-pass optical wavelength signal encoding. The coupled polarized-mode transducer shows how a solid-state sensor can produce narrow-bandpass optical wavelength signal encoding. The luminescent temperature sensor illustrates a way to construct a solid state sensor in order to produce pulse width modulation of an optical signal.
James, K. A.↗
Fiber-optic interferometric acoustic sensors for wind tunnel applications
Progress in developing fiber-optic interferometric sensors for aeroacoustic measurements in wind tunnels, performed under the NASA program, is reported. Preliminary results show that the fiber-optic interferometer sensor array is a powerful instrument for solving complex acoustic measurement problems in wind tunnels, which cannot be resolved with the conventional transducer technique.
Cho, Y. C.↗
Application of new electro-optic technology to Space Station Freedom data management system
A low risk design methodology to permit the local bus structures to support increased data carrying capacities and to speed messages and data flow between nodes or stations on the Space Station Freedom Data Management System in anticipation of growing requirements was evaluated and recommended. The recommended design employs a collateral fiber optic technique that follows a NATO avionic standard that is developed, tested, and available. Application of this process will permit a potential 25 fold increase in data transfer performance on the local wire bus network with a fiber optic network, maintaining the functionality of the low-speed bus and supporting all of the redundant transmission and fault detection capabilities designed into the existing system. The application of wavelength division multiplexing (WDM) technology to both the local data bus and global data bus segments of the Data Management System to support anticipated additional highspeed data transmission requirements was also examined. Techniques were examined to provide a dual wavelength implementation of the fiber optic collateral networks. This dual wavelength implementation would permit each local bus to support two simultaneous high-speed transfers on the same fiber optic bus structure and operate within the limits of the existing protocol standard. A second WDM study examined the use of spectral sliced technology to provide a fourfold increase in the Fiber Distributed Data Interface (FDDI) global bus networks without requiring modifications to the existing installed cable plant. Computer simulations presented indicated that this data rate improvement can be achieved with commercially available optical components.
Husbands, C. R.↗
Identification of Brillouin Zones by In-Plane Lasing from Light-Cone Surface Lattice Resonances
Periodic optical structures can control the flow of light, which has facilitated applications in optical fibers, laser cavities, and biochemical sensors. The first Brillouin zone (BZ) in reciprocal space can describe all the electromagnetic fields localized inside a photonic lattice. However, photonic lattices also exhibit radiative losses from light scattering, but the radiated fields are not captured by the first BZ. In a two-dimensional lattice, the in-plane wavevectors of photonic modes are limited by the so-called light cone, which depicts free-photon dispersion relations in the surrounding medium. Here we show that projection of the light cone on extended BZs provides a geometric method to observe radiated electromagnetic fields of photonic lattice modes. We developed a coupled dipole radiation theory to reveal how lattice geometry and dipole orientation affect the angular distributions of the radiated fields. Using dye molecules as local dipole emitters to excite and probe the optical modes, we experimentally identified high-order BZ edges through directional, in-plane lasing emission.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Active analog tuning of the phase of light in the visible regime by bismuth-based metamaterials
The active and analog tuning of the phase of light by metamaterials is needed to boost the switching performance of photonic devices. However, demonstrations of this type of tuning in the pivotal visible spectral region are still scarce. Herein, we report the active analog tuning of the phase of visible light reflected by a bismuth (Bi)-based metamaterial, enabled by a reversible solid-liquid transition. This metamaterial, fabricated by following a lithography-free approach, consists of twodimensional assemblies of polydisperse plasmonic Bi nanostructures embedded in a refractory and transparent aluminum oxide matrix. The analog tuning of the phase is achieved by the controlled heating of the metamaterial to melt a fraction of the nanostructures. A maximum tuning of 320° (1.8 π) is observed upon the complete melting of the nanostructures at 230°C. This tuning is reversible by cooling to 25°C. In addition, it presents a wide hysteretic character due to liquid Bi undercooling. This enables the phase achieved by this analog approach to remain stable over a broad temperature range upon cooling and until resolidification occurs around 100°C. Therefore, Bi-based metamaterials are endowed with analog optical memory capabilities, which are appealing for a wide range of applications, including optical data storage with enhanced information density or bistable photonic switching with a tunable “on” state.
36 MATERIALS SCIENCE↗
Integrated optics for fiber optic sensors
Recent progress achieved in the field of fiber-optic sensor applications is discussed with emphasis placed on LiNbO3-based integrated optics (IO). Particular consideration is given to advanced electromagnetic-field sensors, an integrated laser vibrometer system, and a fiber-optic gyroscope system. It is shown that the multifunction IO chips have enabled high perforamance fiber-optic sensors (e.g., fiber-optic gyros), provided advanced and unique signal processing capabilities and advanced architectures, and have a potential of making fiber-optic sensors at low cost.
Minford, W. J.↗