Development and accuracy determination of a two-component Doppler Global Velocimeter (DGV)

A two-component Doppler Global Velocimeter (DGV) system was constructed and tested to research problems associated with the accuracy of this unique system. The uniqueness of the system lies in its ability to simultaneously and non-intrusively measure velocities in a laser illuminated plane. A key component of the system is a frequency discriminating optical filter containing iodine vapor which allows direct measurement of the Doppler frequency shift caused by particle motion. Corrections for optical distortions and non-uniform intensities as well as the conversions from intensity data to velocity data are performed by an extensive image processing algorithm. Measurements were made of a 12″ diameter rotating wheel and turbulent pipe/jet flow. Both RMS deviations and velocity range measurement errors from a single component for the rotating wheel with a maximum velocity of 58 m/s were less than 2%, better than most published results, to date, for similar systems. Pipe/jet flow profiles agreed very well with the shape of pitot probe measurements. RMS errors were on the order of 5--10%, but velocity offset error was as much as 10--15% of the 42 m/s velocity range. DGV measured turbulence intensities at the center of the pipe, 4 diameters downstream agreed with hot wire data, with some reservations. Several factors such as repeatability of calibrations, precision of wheel/pipe speed measurement, measurement of viewing angles, and 8-bit camera digitization contributed to the errors in DGV velocity data. Proper techniques for preparing and acquiring correction images are also critical steps toward the goal of producing accurate velocity data

On the integration of deformation and relief measurement using ESPI

The combination of relief and deformation measurement is investigated for improving the accuracy of Electronic Speckle-Pattern Interferometry (ESPI) data. The nature of sensitivity variations within different types of interferometers and with different shapes of objects is analysed, revealing significant variations for some common interferometers. Novel techniques are developed for real-time measurement of dynamic events by means of carrier fringes. This allows quantification of deformation and relief, where the latter is used in the correction of the sensitivity variations of the former

Implementation of a high resolution optical feedback interferometer for microfluidics applications

Recent progress of interferometric sensors based on the optical feedback in a laser diode have demonstrated possibility for measurement of flow rates and flow-profiles at the micro-scale. That type of compact and embedded sensors is very promising for a research and industrial field –microfluidics – that is a growing domain of activities, at the frontiers of the physics, the chemical science, the biology and the biomedical. However, the acquisition of flow rate or local velocity at high resolution remains a very challenging issue, and the sensors that have been proposed so far did not have been giving sufficient information on the nature of the particles flowing. The present thesis is driven to the implementation, validation and evaluation of the sensing performances of the optical feedback interferometry technology in both chemical and biomedical fields of applications. The elaboration of a new generation of sensors that will provide both a high spatial resolution for 2D Doppler imaging is presented, as well as a methodology that gives further information on the flowing particles concentration and/or dimensions. Then, a new embedded optical feedback interferometry imager for flowmetry has been realized using a 2-axis beamsteering mirror mounted on Micro-Electro-Mechanical Systems (MEMS) thus taking the full advantage of the compactness offered by the optical feedback interferometry sensing scheme. While previous works on optical feedback interferometry flowmetry have been limited to high particle densities fluids in single or multiple scattering regimes, we present also a sensing technique based on the optical feedback interferometry scheme in a laser diode that enables single particle detection at micro and nanoscales through the Doppler-Fizeau effect. Thanks to the proposed signal processing, this sensing technique can detect the presence of single spherical polystyrene micro/nanospheres seeded in watery suspensions, and measure their flow velocity, even when their diameter is below half the laser wavelength. It discriminates particle by their diameter up to a ratio of 5 between large and small ones while most of the technologies for particle characterization is bulk and requires manipulation of the fluid with small volume handling, precise flow and concentration control. Altogether, the results presented in this thesis realize a major improvement for the use of optical feedback interferometry in the chemical engineering or biomedical applications involving micro-scale flows

Modern Applications in Optics and Photonics: From Sensing and Analytics to Communication

Optics and photonics are among the key technologies of the 21st century, and offer potential for novel applications in areas such as sensing and spectroscopy, analytics, monitoring, biomedical imaging/diagnostics, and optical communication technology. The high degree of control over light fields, together with the capabilities of modern processing and integration technology, enables new optical measurement systems with enhanced functionality and sensitivity. They are attractive for a range of applications that were previously inaccessible. This Special Issue aims to provide an overview of some of the most advanced application areas in optics and photonics and indicate the broad potential for the future

NASA Tech Briefs, October 2007

Topics covered include; Wirelessly Interrogated Position or Displacement Sensors; Ka-Band Radar Terminal Descent Sensor; Metal/Metal Oxide Differential Electrode pH Sensors; Improved Sensing Coils for SQUIDs; Inductive Linear-Position Sensor/Limit-Sensor Units; Hilbert-Curve Fractal Antenna With Radiation- Pattern Diversity; Single-Camera Panoramic-Imaging Systems; Interface Electronic Circuitry for an Electronic Tongue; Inexpensive Clock for Displaying Planetary or Sidereal Time; Efficient Switching Arrangement for (N + 1)/N Redundancy; Lightweight Reflectarray Antenna for 7.115 and 32 GHz; Opto-Electronic Oscillator Using Suppressed Phase Modulation; Alternative Controller for a Fiber-Optic Switch; Strong, Lightweight, Porous Materials; Nanowicks; Lightweight Thermal Protection System for Atmospheric Entry; Rapid and Quiet Drill; Hydrogen Peroxide Concentrator; MMIC Amplifiers for 90 to 130 GHz; Robot Would Climb Steep Terrain; Measuring Dynamic Transfer Functions of Cavitating Pumps; Advanced Resistive Exercise Device; Rapid Engineering of Three-Dimensional, Multicellular Tissues With Polymeric Scaffolds; Resonant Tunneling Spin Pump; Enhancing Spin Filters by Use of Bulk Inversion Asymmetry; Optical Magnetometer Incorporating Photonic Crystals; WGM-Resonator/Tapered-Waveguide White-Light Sensor Optics; Raman-Suppressing Coupling for Optical Parametric Oscillator; CO2-Reduction Primary Cell for Use on Venus; Cold Atom Source Containing Multiple Magneto- Optical Traps; POD Model Reconstruction for Gray-Box Fault Detection; System for Estimating Horizontal Velocity During Descent; Software Framework for Peer Data-Management Services; Autogen Version 2.0; Tracking-Data-Conversion Tool; NASA Enterprise Visual Analysis; Advanced Reference Counting Pointers for Better Performance; C Namelist Facility; and Efficient Mosaicking of Spitzer Space Telescope Images

Conference Proceedings of the 3rd Biennial Symposium on Turbulence in Liquids

The Third Biennial Symposium on Turbulence in Liquids showed further progress in the investigator\u27s ability to measure turbulence parameters and in the general understanding of turbulence. The most impressive advances in measurement seemed to be the ability to measure deeper into the turbulent boundary layer in order to obtain profiles over the entire turbulence production region and the rapid development of conditioned-sampling techniques for studying hypotheses for mechanisms

Optical Microring Resonators for Photoacoustic Imaging and Detection.

This work is to utilize the superior characteristics of polymer microring resonators in ultrasound detection to push the application of photoacoustic imaging to an entirely new level. We first demonstrated significantly improved imaging quality for photoacoustic tomography (PAT) using microring detectors. For wideband PAT, the microring detectors were able to faithfully detect both the boundaries and the inner structure, while piezoelectric detectors can only preserve one of the two aspects. For high-resolution PAT over a large imaging area, we imaged 50 µm black beads and found that microrings produced high-resolution imaging over a 16-mm-diameter imaging area while the 500 µm piezoelectric detectors only obtained high-resolution imaging over a small area around center. Pure optical photoacoustic microscopy (PAM) has been demonstrated. Microring ultrasonic resonators were applied in in vivo photoacoustic imaging for the first time. Good imaging signal-to-noise ratio and high axial resolution of 8 µm were calibrated. As a comparison, a commercial hydrophone with similar sensitivity produced a low axial resolution of 105 µm. A 5 mm miniaturized probe consisting of a fiber to deliver excitation laser pulses and microring detectors for ultrasound detection has been fabricated for photoacoustic endoscopy. The calibrated high radial resolution of 21 µm was higher than other types of endoscopic photoacoustic probes, around 40 µm or larger. A photoacoustic correlation spectroscopy (PACS) technique was proposed. In a proof-of-concept experiment, we demonstrated low-speed flow measurement of ~15 µm/s by the PACS technique. We also demonstrated in vivo flow speed measurement of red blood cells in capillaries in a chick embryo model by PACS. Other techniques might have difficulties to measure it due to the low signal contrast and/or poor resolutions. We also proposed terahertz electromagnetic pulse detection by photoacoustic method. We used carbon nanotube composites as efficient photoacoustic transmitters and microrings as sensitive detectors. The photoacoustic method provides low-cost and real-time terahertz detection (~µs), which is difficult by conventional terahertz detectors, such as a bolometer or a pyroelectric detector.Ph.D.Electrical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/91497/1/chensll_1.pd