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Channeled spectropolarimetry using iterative reconstruction

Proceedings of SPIE - The International Society for Optical Engineering

Lee, Dennis J.; Lacasse, Charles F.; Craven, Julia M.

Channeled spectropolarimeters (CSP) measure the polarization state of light as a function of wavelength. Conventional Fourier reconstruction suffers from noise, assumes the channels are band-limited, and requires uniformly spaced samples. To address these problems, we propose an iterative reconstruction algorithm. We develop a mathematical model of CSP measurements and minimize a cost function based on this model. We simulate a measured spectrum using example Stokes parameters, from which we compare conventional Fourier reconstruction and iterative reconstruction. Importantly, our iterative approach can reconstruct signals that contain more bandwidth, an advancement over Fourier reconstruction. Our results also show that iterative reconstruction mitigates noise effects, processes non-uniformly spaced samples without interpolation, and more faithfully recovers the ground truth Stokes parameters. This work offers a significant improvement to Fourier reconstruction for channeled spectropolarimetry.

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TYPE Conference Poster YEAR 2016
OSTIScopus

Transformation of amorphous TiO2 to a hydronium oxofluorotitanate and applications as an HF sensor

Sensors and Actuators. B, Chemical

Appelhans, Leah A.; Finnegan, Patrick S.; Massey, Lee T.; Luk, Ting S.; Rodriguez, Mark A.; Brumbach, Michael T.; McKenzie, Bonnie B.; Craven, Julia M.

We examined amorphous titania thin films for use as the active material in a polarimetry based HF sensor. The amorphous titania films were found to be sensitive to vapor phase HF and the reaction product was identified as a hydronium oxofluorotitanate phase, which has previously only been synthesized in aqueous solution. The extent of reaction varied both with vapor phase HF concentration, relative humidity, and the exposure time. HF concentrations as low as 1 ppm could be detected for exposure times of 120 h.

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TYPE Journal Article YEAR 2015
DOIOSTI
Results 26–46 of 46
Results 26–46 of 46