Erik Moro | Los Alamos National Laboratory (original) (raw)

Papers by Erik Moro

SHOCK COMPRESSION OF CONDENSED MATTER - 2019: Proceedings of the Conference of the American Physical Society Topical Group on Shock Compression of Condensed Matter

... Modulated Fiber Optic Displacement Sensors Ph.D. Thesis Defense LA-UR 12-XXXXX Erik Moro, Ph.... more ... Modulated Fiber Optic Displacement Sensors Ph.D. Thesis Defense LA-UR 12-XXXXX Erik Moro, Ph.D. Candidate Advisor: Professor Michael Todd (UCSD, SE) LANL Mentor: Dr. Anthony Puckett (LANL, W-3) 06/15/2012 Page 3. ABSTRACT ...

Journal of Physics Conference Series

Photon Doppler velocimetry (PDV) has made the transition among many experimental groups from bein... more Photon Doppler velocimetry (PDV) has made the transition among many experimental groups from being a new diagnostic to being routinely fielded as a means of obtaining velocity data in high-speed test applications. Indeed, research groups both within and outside of the shock physics community have taken note of PDV's robust, high-performance measurement capabilities. As PDV serves as the primary diagnostic in an increasing number of experiments, it will continue to find new applications and enable the measurement of previously un-measurable phenomena. This paper provides a survey of recent developments in PDV system design and feature extraction as well as a discussion of new applications for PDV. More specifically, changes at the system level have enabled the collection of data sets that are far richer than those previously attainable in terms of spatial and temporal coverage as well as improvements over PDV's previously measurable velocity ranges. And until recently, PDV da...

Proceedings of Spie the International Society For Optical Engineering, Mar 26, 2009

... Proceedings Vol. 7288. Active and Passive Smart Structures and Integrated Systems 2009, Mehdi... more ... Proceedings Vol. 7288. Active and Passive Smart Structures and Integrated Systems 2009, Mehdi Ahmadian; Mehrdad N. Ghasemi-Nejhad, Editors, 728810. Date: 6 April 2009. Paper Abstract. In this paper, we present experimental ...

ABSTRACT A testbed simulating an intensity-modulated fiber optic displacement sensor is experimen... more ABSTRACT A testbed simulating an intensity-modulated fiber optic displacement sensor is experimentally characterized, and the implications regarding sensor design are discussed. Of interest are the intensity distribution of the transmitted optical signal and the relationships between sensor architecture and performance. Particularly, an intensity-modulated sensor's sensitivity, linearity, displacement range, and resolution are functions of the relative positioning of its transmitting and receiving fibers. In this paper, sensor architectures with various combinations of these performance metrics are discussed. A sensor capable of micrometer resolution is reported, and it is concluded that this work could lead to an improved methodology for sensor design.

Smart Sensor Phenomena, Technology, Networks, and Systems Integration 2012, 2012

ABSTRACT Bundled intensity-modulated fiber optic displacement sensors offer high-speed (kHz-MHz) ... more ABSTRACT Bundled intensity-modulated fiber optic displacement sensors offer high-speed (kHz-MHz) performance with micrometer-level accuracy over a broad range of axial displacements, and they are particularly well-suited for applications where minimally invasive, non-contacting sensing is desired. Furthermore, differential versions of these sensors have the potential to contribute robustness to fluctuating environmental conditions. The performance limitations of these sensors are governed by the relationship between axial displacement and measured power at the locations of receiving fibers within a bundled probe. Since the propagating transmission's power level is spatially non-uniform, the relative locations of receiving fibers within a bundled probe are related to the sensor's output, and in this way fiber location is related to sensor performance. In this paper, measured power levels are simulated using a validated optical transmission model, and a genetic algorithm is employed for searching the intensity-modulated bundled displacement sensor's design space for bundle configurations that offer high-overall combinations of desired performance metrics (e.g., linearity, sensitivity, accuracy, axial displacement range, etc...). The genetic algorithm determines arrangements of fibers within the bundled probe that optimize a performance-based cost function and have the potential to offer high-performance operation. Multiple converged results of the genetic algorithm generated using different cost function structures are compared. Two optimized configurations are prototyped, and experimental sensor performance is related to simulated performance levels. The prototypes' linearity, sensitivity, accuracy, axial displacement range, and sensor robustness are described, and sensor bandwidth limitations are discussed. This paper has been approved by Los Alamos National Laboratory for unlimited public distribution (LA-UR 12-00642).

Fiber Optic Sensors and Applications IX, 2012

ABSTRACT Non-contacting interferometric fiber optic sensors offer a minimally invasive, high-accu... more ABSTRACT Non-contacting interferometric fiber optic sensors offer a minimally invasive, high-accuracy means of measuring a structure's kinematic response to loading. The performance of interferometric sensors is often dictated by the technique employed for demodulating the kinematic measurand of interest from phase in the observed optical signal. In this paper a white-light extrinsic Fabry-Perot interferometer is implemented, offering robust displacement sensing performance. Displacement data is extracted from an estimate of the power spectral density, calculated from the interferometer's received optical power measured as a function of optical transmission frequency, and the sensor's performance is dictated by the details surrounding the implementation of this power spectral density estimation. One advantage of this particular type of interferometric sensor is that many of its control parameters (e.g., frequency range, frequency sampling density, sampling rate, etc.) may be chosen to so that the sensor satisfies application-specific performance needs in metrics such as bandwidth, axial displacement range, displacement resolution, and accuracy. A suite of user-controlled input values is investigated for estimating the spectrum of power versus wavelength data, and the relationships between performance metrics and input parameters are described in an effort to characterize the sensor's operational performance limitations. This work has been approved by Los Alamos National Laboratory for unlimited public release (LA-UR 12-01512).

21st International Conference on Optical Fiber Sensors, 2011

2013 IEEE SENSORS, 2013

ABSTRACT We recently demonstrated that a single optical probe is capable of simultaneously measur... more ABSTRACT We recently demonstrated that a single optical probe is capable of simultaneously measuring a surface's velocity along the beam axis and its speed transverse to the beam axis. Doppler shifts in the measured data are related to axial motion, while intensity fluctuations, induced by speckle dynamics, are related to transverse motion. While it is readily apparent that speckle dynamics manifest themselves in the measured data, the ability to extract transverse speed from a particular (speckle-induced) signal feature is feature-dependent. In this paper, we relate a signal's coherence, variance, and frequency content to surface dynamics, in an effort to determine the suitability of each of these features for calculating transverse motion (classification release number: LA-UR 13-26315).

The Review of scientific instruments, 2013

A method is introduced for simultaneously measuring transverse speed and axial velocity using a s... more A method is introduced for simultaneously measuring transverse speed and axial velocity using a single optical beam and a standard photon Doppler velocimetry (PDV) sensing architecture. This result is of particular interest given the recent, widespread use of PDV and the fact that optical velocimetry has thus far been limited to measuring motion in one dimension per probe. Further, this result demonstrates that both axial velocity data and transverse speed data (at least qualitative) may be obtained entirely through signal analysis; not requiring hardware modification. This result is immediately relevant to analyses of existing PDV data and to future efforts in high-speed optical velocimetry.

Applied optics, Jan 20, 2014

Historically, single-beam optical velocimetry has been limited to measuring only the component of... more Historically, single-beam optical velocimetry has been limited to measuring only the component of velocity along the beam. However, theoretical work and recent experimental results have shown that laser speckle dynamics may be exploited to measure lateral motion, thereby gaining information about surface dynamics across an additional degree of freedom. In the use of photon Doppler velocimetry (PDV), this new information is considered "free" in that it is already contained within the PDV signal, needing only to be extracted and interpreted correctly. In this manuscript, we relate speckle dynamics to the lateral motion of a planar scattering surface in the PDV coordinate system via the space-time correlation function of the diffracted electric field. Next, we relate the characteristic time scale of speckle intensity fluctuations in the PDV signal to the rate of lateral surface translation and to parameters characterizing the optical probe. Analytical results are compared wit...

Conference Proceedings of the Society for Experimental Mechanics Series, 2011

, University of New Mexico, 4000 University Dr., Albuquerque, NM 87131 b University of California... more , University of New Mexico, 4000 University Dr., Albuquerque, NM 87131 b University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093'Rose-Hulman Institute of Technology, 5500 Wabash Ave., Terra Heute, IN 47803 d Los Alamos National Laboratory ...

Conference Proceedings of the Society for Experimental Mechanics Series, 2014

Journal of Physics: Conference Series, 2014

ABSTRACT Optical velocimetry is limited to measuring the component of the target velocity along t... more ABSTRACT Optical velocimetry is limited to measuring the component of the target velocity along the axis of the optical beam, thereby allowing a laterally moving tilted surface to approach a probe undetected. We are not discussing the detection of the lateral motion, but rather the detection of material approaching the probe due to lateral motion of a surface that is not perpendicular to the beam. This motion is not measured in optical velocimetry, and consequentially, integrating the velocity will in general give an incorrect position. We will present three approaches to overcome this limitation: Tilted wave-front interferometry, which maps time of flight into fringe displacement; pulse bursts for which we measure the change in the average arrival time of a burst, and amplitude modulation interferometry, in which a change in path length shows up as a change in the phase of the modulation. All three of these have the potential to be integrated with existing velocimetry probes for simultaneous velocity and displacement measurements. We will also report on initial tests of these approaches.