@article{kudenov_pantalone_yang_2020, title={Dual-beam potassium Voigt filter for atomic line imaging}, volume={59}, ISSN={["2155-3165"]}, DOI={10.1364/AO.393649}, abstractNote={Spectrally narrowband imaging in remote sensing applications can be advantageous for detecting atomic emission features. This is especially useful in detecting specific constituents within rocket plumes, which are challenging to discern from naturally occurring sunglints. In this paper, we demonstrate a dual-beam technique, implemented with a Wollaston prism, for calibrating a Voigt magneto-optical filter for a linear polarizer’s finite extinction ratio, as well as optical misalignment between the linear polarizers’ transmission axes. Such a strategy would be key towards expanding the filter’s field of view while maintaining its classification capabilities. Validation of the potassium Voigt filter is demonstrated using the simulation tool ElecSus in combination with a potassium hollow cathode lamp. RMS error between the filter’s temperature response and that of the simulation was approximately 2%. We then demonstrate the detection of a potassium model rocket motor outdoors alongside a sunglint. Results indicate a 20-fold increase in contrast when using our dual-beam calibration strategy.}, number={17}, journal={APPLIED OPTICS}, author={Kudenov, Michael W. and Pantalone, Brett and Yang, Ruonan}, year={2020}, month={Jun}, pages={5282–5289} }
 @article{yang_sen_o'connor_kudenov_2020, title={Optimization of an intrinsic coincident polarimeter and quantitative architectural comparison of different polarimeter techniques}, volume={59}, ISSN={["1560-2303"]}, DOI={10.1117/1.OE.59.2.024111}, abstractNote={Abstract. Polarimeters have broad applications in remote sensing, astronomy, and biomedical imaging to measure a scene’s polarization state. An intrinsic coincident (IC) full-Stokes polarimeter was previously demonstrated and optimized to achieve high temporal and spatial resolution. We optimized the IC polarimeter by introducing additional waveplates or measurement channels and compared it with existing polarimeter architectures under signal-independent Gaussian noise and signal-dependent Poisson noise. The quantitative comparison of noise variances showed that the IC and division-of-amplitude polarimeters have the lowest noise variances due to their higher signal collection ability. Both polarimeters have a factor of 2 and 2 improved signal-to-noise ratio, in the S0 component, for Gaussian and Poisson noises, respectively, as compared to division of time, division of focal plane, and division of aperture polarimeters. While the division of amplitude and IC polarimeters outperforms other approaches, the IC polarimeter has a significantly simpler design, potentially allowing for cost-effective, high-performance polarimetric imaging.}, number={2}, journal={OPTICAL ENGINEERING}, author={Yang, Ruonan and Sen, Pratik and O'Connor, Brendan and Kudenov, Michael}, year={2020}, month={Feb} }
 @article{yang_sen_brendan t. o'connor_kudenov_2020, title={Optical crosstalk and off-axis modeling of an intrinsic coincident polarimeter}, volume={59}, ISSN={["2155-3165"]}, DOI={10.1364/AO.59.000156}, abstractNote={Polarimeters have broad applications in remote sensing, astronomy, and biomedical imaging to measure the emitted, reflected, or transmitted state of polarization. An intrinsic coincident (IC) full-Stokes polarimeter was previously demonstrated by our group, in a free space configuration, by using stain-aligned polymer-based organic photovoltaics. To minimize the model’s complexity, these were tilted to avoid crosstalk from back-reflections. We present a theoretical model of a monolithic IC polarimeter that considers the back-reflection’s influence for on-axis light. The model was validated using a monolithic four-detector polarimeter, which achieved an error of less than 3%. Additionally, an off-axis model was produced and validated for a simpler two detector polarimeter, demonstrating an error between the TM and TE polarized components of less than 3% for angles spanning an 18° incidence cone.}, number={1}, journal={APPLIED OPTICS}, author={Yang, Ruonan and Sen, Pratik and Brendan T. O'Connor and Kudenov, Michael W.}, year={2020}, month={Jan}, pages={156–164} }
 @article{sen_yang_rech_feng_ho_huang_so_kline_you_kudenov_et al._2019, title={Panchromatic All-Polymer Photodetector with Tunable Polarization Sensitivity}, volume={7}, ISSN={["2195-1071"]}, DOI={10.1002/adom.201801346}, abstractNote={AbstractIn this report, a high‐performance all‐polymer organic photodetector that is sensitive to linearly polarized light throughout the visible spectrum is demonstrated. The active layer is a bulk heterojunction composed of an electron donor polymer PBnDT‐FTAZ and acceptor polymer P(NDI2OD‐T2) that have complementary spectral absorption resulting in efficient detection from 350 to 800 nm. The blend film exhibits good ductility with the ability to accommodate large strains of over 60% without fracture. This allows the film to undergo large uniaxial strain resulting in in‐plane alignment of both polymers making the film optically anisotropic and intrinsically polarization sensitive. The films are characterized by UV–vis spectroscopy and grazing incidence wide‐angle X‐ray scattering showing that both polymers have similar in‐plane backbone alignment and maintain packing order after being strained. The films are integrated into devices and characterized under linear polarized light. The strain‐oriented detectors have maximum photocurrent anisotropies of 1.4 under transverse polarized light while maintaining peak responsivities of 0.21 A W−1 and a 3 dB cutoff frequency of ≈1 kHz. The demonstrated performance is comparable to the current state of the art all‐polymer photodetectors with the added capability of polarization sensitivity enabling new application opportunities.}, number={4}, journal={ADVANCED OPTICAL MATERIALS}, author={Sen, Pratik and Yang, Ruonan and Rech, Jeromy J. and Feng, Yuanxiang and Ho, Carr Hoi Yi and Huang, Jinsong and So, Franky and Kline, R. Joseph and You, Wei and Kudenov, Michael W. and et al.}, year={2019}, month={Feb} }
 @article{yang_sen_o'connor_kudenov_2017, title={Intrinsic coincident full-Stokes polarimeter using stacked organic photovoltaics}, volume={56}, ISSN={["2155-3165"]}, DOI={10.1364/ao.56.001768}, abstractNote={An intrinsic coincident full-Stokes polarimeter is demonstrated by using strain-aligned polymer-based organic photovoltaics (OPVs) that can preferentially absorb certain polarized states of incident light. The photovoltaic-based polarimeter is capable of measuring four Stokes parameters by cascading four semitransparent OPVs in series along the same optical axis. This in-line polarimeter concept potentially ensures high temporal and spatial resolution with higher radiometric efficiency as compared to the existing polarimeter architecture. Two wave plates were incorporated into the system to modulate the S3 Stokes parameter so as to reduce the condition number of the measurement matrix and maximize the measured signal-to-noise ratio. Radiometric calibration was carried out to determine the measurement matrix. The polarimeter presented in this paper demonstrated an average RMS error of 0.84% for reconstructed Stokes vectors after normalized to S0. A theoretical analysis of the minimum condition number of the four-cell OPV design showed that for individually optimized OPV cells, a condition number of 2.4 is possible.}, number={6}, journal={APPLIED OPTICS}, author={Yang, Ruonan and Sen, Pratik and O'Connor, B. T. and Kudenov, M. W.}, year={2017}, month={Feb}, pages={1768–1774} }
 @article{yang_sen_o'connor_kudenov_2017, title={Intrinsic coincident full-Stokes polarimeter using stacked organic photovoltaics and architectural comparison of polarimeter techniques}, volume={10407}, ISBN={["978-1-5106-1271-6"]}, ISSN={["1996-756X"]}, DOI={10.1117/12.2273885}, abstractNote={An intrinsic coincident full-Stokes polarimeter is demonstrated by using stain-aligned polymer-based organic photovoltaics (OPVs) which can preferentially absorb certain polarized states of incident light. The photovoltaic-based polarimeter is capable of measuring four stokes parameters by cascading four semitransparent OPVs in series along the same optical axis. Two wave plates were incorporated into the system to modulate the S3 stokes parameter so as to reduce the condition number of the measurement matrix. The model for the full-Stokes polarimeter was established and validated, demonstrating an average RMS error of 0.84%. The optimization, based on minimizing the condition number of the 4-cell OPV design, showed that a condition number of 2.4 is possible. Performance of this in-line polarimeter concept was compared to other polarimeter architectures, including Division of Time (DoT), Division of Amplitude (DoAm), Division of Focal Plane (DoFP), and Division of Aperture (DoA) from signal-to-noise ratio (SNR) perspective. This in-line polarimeter concept has the potential to enable both high temporal (as compared with a DoT polarimeter) and high spatial resolution (as compared with DoFP and DoA polarimeters). We conclude that the intrinsic design has the same ~√2 SNR advantage as the DoAm polarimeter, but with greater compactness.}, journal={POLARIZATION SCIENCE AND REMOTE SENSING VIII}, author={Yang, Ruonan and Sen, Pratik and O'Connor, B. T. and Kudenov, M. W.}, year={2017} }