Publications & Presentations

Investigation of middle ear anatomy and function with combined video otoscopy-phase sensitive OCT

Jesung Park, Jeffrey T. Cheng, Daniel Ferguson, Gopi Maguluri, Ernest W. Chang, Caitlin Clancy, Daniel J. Lee, and Nicusor Iftimia
Biomedical Optics Express 238, Vol. 7, No. 2 | DOI:10.1364/BOE.7.000238

We report the development of a novel otoscopy probe for assessing middle ear anatomy and function. Video imaging and phasesensitive optical coherence tomography are combined within the same optical path. A sound stimuli channel is incorporated as well to study middle ear function.

Thus, besides visualizing the morphology of the middle ear, the vibration amplitude and frequency of the eardrum and ossicles are retrieved as well. Preliminary testing on cadaveric human temporal bone models has demonstrated the capability of this instrument for retrieving middle ear anatomy with micron scale resolution, as well as the vibration of the tympanic membrane and ossicles with sub-nm resolution

Cooperative use of standoff and UAV sensors for CBRNE detection

William J. Marinelli, Thomas Schmit, Julia Rentz Dupuis, Phil Mulhall, Philly Croteau, David Manegold, Manal Beshay, and Marvin Lav
Cooperative use of standoff and UAV sensors for CBRNE detection
SPIE DSS Defense & Security, 20-24 April 2015, Baltimore, MD

The defense of the US armed forces against chemical and biological (CB) attack is transitioning from a focus on standoff detection of these threats to the concept of Early Warning (EW). In this approach an array of dual-use and low-burden dedicated use sensor capabilities are used to replace longer-range single use sensors to detect a CB attack.

In this paper we discuss the use of passive broadband thermal imaging to detect chemical vapor clouds as well as a developing suite of compact UAV-borne chemical and radiological sensors for the investigation of threats detected by these indirect approaches. The sensors include a colorimetric ammonia sensor, a chemical sensor based on ion mobility spectrometry, and a radiation detector based on gamma ray scintillation. The implementation and initial field tests of each of these sensor modalities is discussed and future plans for the further development of the capability is presented.

Large, Deployable S-Band Antenna for a 6U Cubesat

Peter A. Warren, John W. Stevinbeck, Robert J. Minelli, and Carl Mueller
Large, Deployable S-Band Antenna for a 6U Cubesat
29th Annual AIAA/USU Conference on Small Satellites, Logan, UT, August 8-13, 2015

Small satellites in general and cubesats in particular have been limited in their ability to perform RF science and communications missions by the size of the RF aperture. A large deployable membrane antenna approach has been developed to address the limits in aperture size and provide both high gain communications and sensing from UHF to C-band.

The paper describes the general approach and presents performance results from ground test articles of an S-Band implementation of the architecture. The test article deploys a 1.53 m2 active area out of a 2U (2,000 cm3) volume from a 6U cubesat. The antenna array is formed from two tensioned membranes. The membranes are folded compactly for launch along with four deployable boom structures. Once on orbit, the booms deploy, unfolding and tensioning the membranes and then hold them in place for operation. Ground test articles have shown a gain of 30.5 dB at 3.6 GHz. The antenna has a 3 dB beamwidth of 3.4°, has an overall aperture efficiency of 56% and sidelobes 10 dB lower than the main lobe. The system architecture can be applied to payload volumes as small as ½U and to frequencies from UHF to K-band.

Longwave Infrared Compressive Hyperspectral Imager

Julia R. Dupuis, Michael Kirby, and Bogdan R. Cosofret
Longwave Infrared Compressive Hyperspectral Imager
SPIE DSS Defense & Security, 20-24 April 2015, Baltimore, MD

Physical Sciences Inc. (PSI) is developing a longwave infrared (LWIR) compressive sensing hyperspectral imager (CS HSI) based on a single pixel architecture for standoff vapor phase plume detection.

The sensor employs novel use of a high throughput stationary interferometer and a digital micromirror device (DMD) converted for LWIR operation in place of the traditional cooled LWIR focal plane array. The CS HSI represents a substantial cost reduction over the state of the art in LWIR HSI instruments. Radiometric improvements for using the DMD in the LWIR spectral range have been identified and implemented. In addition, CS measurement and sparsity bases specifically tailored to the CS HSI instrument and chemical plume imaging have been developed and validated using LWIR hyperspectral image streams of chemical plumes. These bases enable comparable statistics to detection based on uncompressed data.

In this paper, we present a system model predicting the overall performance of the CS HSI system. Results from a breadboard build and test validating the system model are reported. In addition, the measurement and sparsity basis work demonstrating the plume detection on compressed hyperspectral images is presented

Optically Pumped Microplasma Rare Gas Laser

W. T. Rawlins1, K. L. Galbally-Kinney, S. J. Davis1 A. R. Hoskinson, J. A. Hopwood, and M. C. Heaven, Optically pumped microplasma rare gas laser, Optics Express Vol. 23(4) 4804-4813, 2015
The optically pumped rare-gas metastable laser is a chemically inert analogue to three-state optically pumped alkali laser systems. The concept requires efficient generation of electronically excited metastable atoms in a continuous-wave (CW) electric discharge in flowing gas mixtures near atmospheric pressure.
We have observed CW optical gain and laser oscillation at 912.3 nm using a linear micro-discharge array to generate metastable Ar(4s, 1s5) atoms at atmospheric pressure. We observed the optical excitation of the 1s5 → 2p9 transition at 811.5 nm and the corresponding fluorescence, optical gain and laser oscillation on the 2p10 ↔ 1s5 transition at 912.3 nm, following 2p9→2p10 collisional energy transfer. A steady-state kinetics model indicates efficient collisional coupling within the Ar(4s) manifold.