Linear Diattenuation Research Articles

Gold nanoparticle-based biosensor for Lysozyme-DNA detection utilizing decomposition Mueller matrix polarimetry

Lysozyme serves as a crucial biomarker in the identification of several diseases, that includes breast cancer, Alzheimer’s disease, meningitis, and rheumatoid arthritis. This study proposes an innovative method for the detection of Lysozyme using a gold nanoparticle based biosensor and decomposition Muller matrix polarimetry. In the proposed study, the DNA aptamer is used as the recognition element, while the gold nanoparticles are used as a sensing element. The sensed signal is taken as the input to a Mueller matrix calculation process, which determines three optical characteristics that yield optimal results of the gold nanoparticle colloidal solution, namely the degree of depolarization, the linear diattenuation, and the depolarization index. The results have shown that all three optical parameters vary linearly with the concentration of Lysozyme throughout a broad dynamic range spanning from 0.01 to 500 pM with a limit of detection of 1.24 fM. Overall, the proposed technique provides potential tool for the detection of Lys.

Mueller matrix-based characterization of cervical tissue sections: a quantitative comparison of polar and differential decomposition methods.

Quantitative optical polarimetry has received considerable recent attention owing to its potential for being an efficient diagnosis and characterizing tool with potential applications in biomedical research and various other disciplines. In this regard, it is crucial to validate various Mueller matrix (MM) decomposition methods, which are utilized to extract and quantify the intrinsic individual polarization anisotropy properties of various complex optical media. To quantitatively compare the performance of both polar and differential MM decomposition methods for probing the structural and morphological changes in complex optical media through analyzing their intrinsic individual polarization parameters, which are extracted using the respective decomposition algorithms. We also intend to utilize the decomposition-derived anisotropy parameters to distinguish among the cervical tissues with different grades of cervical intraepithelial neoplasia (CIN) and to characterize the healing efficiency of an organic crystal. Polarization MM of the cervical tissues with different grades of CIN and the different stages of the self-healing crystal are recorded with a home-built MM imaging setup in the transmission detection geometry with a spatial resolution of . The measured MMs are then processed with both the polar and differential MM decomposition methods to extract the individual polarization parameters of the respective samples. The derived polarization parameters are further analyzed to validate and compare the performance of both the MM decomposition methods for probing and characterizing the structural changes in the respective investigated optical media through their decomposition-derived intrinsic individual polarization properties. Pronounced differences in the decomposed-derived polarization anisotropy parameters are observed for cervical tissue sections with different grades of CIN. While a significant increase in the depolarization parameter is obtained with the increment of CIN stages for both the polar [ for CIN grade one (CIN-I) and for CIN grade two (CIN-II))] and differential ( for CIN-I and for CIN-II) decomposition methods, a trend reversal is seen for the linear diattenuation parameter , indicating the structural distortion in the cervical morphology due to the CIN disease. More importantly, with the differential decomposition algorithm, the magnitude of the derived parameter decreases from 0.26 to 0.19 with the progression of CIN, which was not being probed by the polar decomposition method. Our results demonstrate that the differential decomposition of MM holds certain advantages over the polar decomposition method to characterize and probe the structural changes in the cervical tissues with different grades of CIN. Although the quantified individual polarization parameters obtained through both the MM decomposition methods can be used as useful metrics to characterize various optical media, in case of complex turbid media such as biological tissues, incorporation of the differential decomposition technique may yield more efficient information. Also, the study highlights the utilization of MM polarimetry with an appropriate decomposition technique as an efficient diagnostic and characterizing tool in the realm of biomedical clinical research, and various other disciplines.

Polarization calibration of the Tandem Etalon Magnetograph of the Solar Magnetic Activity Research Telescope at Hida Observatory

Abstract The Tandem Etalon Magnetograph (TEM) is one of the instruments of the Solar Magnetic Activity Research Telescope of Hida Observatory. The TEM is a partial disk (320″ × 240″) filter magnetograph which scans the wavelength around a Fe i line at 6303 Å and achieves polarimetric sensitivity of <5 × 10−4 for each wavelength. To obtain the polarimeter response matrix of the instrument, we have carried out end-to-end polarization calibrations of the instrument. We have also measured the polarization characteristics of the polarization beam splitter (PBS), which is a crucial component of the instrument. As a result of end-to-end calibration, we found significant spatial variation in the response matrix across the field of view. From a laboratory test, we found that $1\%$ of the magnitude of a circular diattenuation of the PBS was due to the retardation caused by the stress in the cube and the linear diattenuation of the film. Although the spatial variation across the field of view is more than 10 times larger, to achieve the polarimetric sensitivity of <5 × 10−4, this can be well explained by the polarization characteristic of the PBS and corrected by using the response matrix obtained in the end-to-end calibration. In addition, we also obtained the daily variation of the polarization property of the TEM. We found that the crosstalk from Stokes Q to V changes by an amount comparable to the tolerance through a day. In the present configuration, we require a pixel-by-pixel calibration every 100 min to meet the accuracy requirement.

Linear retardance and diattenuation dispersion measurements of anisotropic medium with Jones calculus based spectrometric technique

A white light spectrometric technique based on the Jones Calculus (JC) formalism using channelled transmission spectra has been developed to measure the linear retardance (LR) and diattenuation (LD) of a Mylar film, widely used for liquid crystal display devices. The sample was placed between two identical polarizers and the channelled spectra of two different configurations (parallel and crossed) were recorded. Transmitted light intensity data over a broad visible spectral range of both channelled spectra were then combined in order to derive the dispersion of retardance and diattenuation of the Mylar film with respect to the wavelength. This technique is fast, easy to setup, and straightforward; and the proposed model, based on the Jones formalism, offers an intuitive and simple calculation, particularly because, unlike other models based on the Mueller calculus, Jones matrices have simpler properties and are more easily manipulated and interpreted. Moreover, the technique provides a complete analytical formulation of transmitted light intensity taking into account the diattenuation defect in both polarizers and sample.

Electrically rotated retarder/diattenuator system for application to a variety of polarization elements

This study presents an optical system equivalent to a polarization element, which can be applied as a linear phase retarder with arbitrary phase retardation or a linear diattenuator with arbitrary diattenuation. The principal axis of the equivalent polarization element can be rotated by applying an electrical signal to an electro-optic modulator. The simple optical system setup is only composed of three polarization elements in a round-trip configuration. The proposed system is versatile, in that it can be applied to a variety of polarization elements that have linear anisotropy.

Linear diattenuation imaging of biological samples with digital lensless holographic microscopy.

A digital lensless holographic microscope (DLHM) sensitive to the linear diattenuation produced by biological samples is reported. The insertion of a linear polarization-states generator and a linear polarization-states analyzer in a typical DLHM setup allows the proper linear diattenuation imaging of microscopic samples. The proposal has been validated for simulated and experimental biological samples containing calcium oxalate crystals extracted from agave leaves and potato starch grains. The performance of the proposed method is similar to that of a traditional polarimetric microscope to obtain linear diattenuation images of microscopic samples but with the advantages of DLHM, such as numerical refocusing, cost effectiveness, and the possibility of field-portable implementation.

Diattenuation and retardance signature of plasmonic gold nanorods in turbid media revealed by Mueller matrix polarimetry

Plasmonic gold nanorods (GNRs) are finding increasing use in biomedicine due to their unique electromagnetic properties, optical contrast enhancement and biocompatibility; they also show promise as polarization contrast agents. However, quantification of their polarization-enhancing properties within heterogeneous turbid media remains challenging. We report on polarization response in controlled tissue phantoms consisting of dielectric microsphere scatterers with varying admixtures of GRNs. Experimental Mueller matrix measurements and polarization sensitive Monte-Carlo simulations show excellent agreement. Despite the GNRs’ 3D random orientation and distribution in the strong multiply scattering background, significant linear diattenuation and retardance were observed. These exclusive measurable characteristics of GNRs suggest their potential uses as contrast enhancers for polarimetric assessment of turbid biological tissue.

Patterned liquid crystal polymer C-plate retarder and color polarizer.

The patternability and guest-host interaction with dichroic dye and C-plate liquid crystal polymer (LCP) materials are investigated, and the optical properties of a thin film C-plate retarder and polarizer are studied and compared with theory. The C-plate retarder is a waveplate made of a uniaxial LCP where the optical axis of the LCP is parallel to the surface normal of the optic. No retardance is observed at a normal angle of incidence and retardance grows as the angle of incidence increases. The C-plate polarizer is a C-plate retarder with LCP as the host and a dichroic dye as the guest. The linear diattenuation (LD) of the linear polarizer is zero at a normal angle of incidence and grows with an increasing angle of incidence. Both the C-plate retarder and polarizer can be patterned with minimum feature size down to 2 µm by using ultraviolet photolithography and plasma etching. A planarization process is also developed to deposit a cover layer on top of the pattern to reduce optical loss and to serve as a barrier for subsequent layers.

Orthogonal-polarization-gating optical coherence tomography for human sweat ducts in vivo.

We propose an orthogonal-polarization-gating optical coherence tomography (OPG-OCT) for human sweat ducts in vivo. OPG-OCT is composed of the orthogonal linearly polarized light of a sample arm individually interfering with orthogonal linearly polarized lights of the reference arms, where OPG-OCT induces two images, one reflecting the projection intensity and the other the horizontal linear diattenuation (HLD). The results demonstrate that OPG-OCT projection intensity could improve the image quality of sweat ducts. HLD also clearly illustrates the spiral shape of the sweat ducts. Finally, sweat ducts in intensity image are segmented by employing convolutional neural networks (CNN). The proportions of left-handed and right-handed ducts are extracted to characterize the sweat ducts based on HLD. Therefore, the OPG-OCT technique employing CNN for the human sweat glands has the potential to automatically identify the human sweat ducts in vivo.

Linear diattenuation imaging of biological tissues with near infrared Mueller scanning microscopy.

Among the multitude of optical polarization contrasts that can be observed in complex biological specimens, linear diattenuation (LD) imaging has received little attention. It is indeed challenging to image LD with basic polarizing microscopes because it is often relatively small in comparison with linear retardance (LR). In addition, interpretation of LD images is not straightforward when experiments are conducted in the visible range because LD can be produced by both dichroism and anisotropic scattering. Mueller polarimetry is a powerful implementation of polarization sensing able to differentiate and measure the anisotropies of specimens. In this article, near infrared transmission Mueller scanning microscopy is used to image LD in thin biological specimen sections made of various proteins with unprecedented resolution and sensitivity. The near infrared spectral range makes it possible to lower the contribution of dichroism to the total linear diattenuation in order to highlight anisotropic scattering. Pixel-by-pixel comparison of LD images with LR and multiphoton images demonstrates that LD is produced by under-resolved structures that are not revealed by other means, notably within the sarcomere of skeletal muscles. LD microscopy appears as a powerful tool to provide new insights into the macro-molecular organization of biological specimens at the sub-microscopic scale without labelling.

Simultaneous balancing of geometric transformation and linear polarizations using six-fold-mirror geometry over the visible region.

The presence of optical rotation due to the Berry phase and coating-induced linear polarizations across a set of rays deteriorate the form of a point spread function. In this Letter, we model an optical system with six aluminum coated fold mirrors, and we show how to balance geometric transformation, linear retardance, and linear diattenuation simultaneously. We minimize the linear polarizations by arranging the six fold mirrors in three pairs of crossed-fold-mirror geometry. In the same optical model, we also show that geometric transformation induced by the first set of three mirrors is canceled out by the second set of three mirrors by rotating the eigen-polarizations in opposite direction with the same amount. We perform experimental verification using a spectroscopic Mueller matrix polarimeter over the visible spectral range.

Native oxide layer effect on polarization cancellation for mirrors over the visible to near-infrared region

Abstract The presence of native oxide layers on aluminum mirrors can be a nuisance for precision optical design. As the native oxide thickness varies from mirror to mirror, its effect cannot be completely canceled even in the conventional crossed fold mirror geometry. We show how this effect arises and how it can be mitigated, and provide an experimental demonstration in which the residual linear retardance and linear diattenuation are reduced to <0.14° and <0.001, respectively, over the visible and near-infra-red spectral range.

Mapping of retardance, diattenuation and polarizance vector on Poincare sphere for diagnosis and classification of cervical precancer.

The mapping of diattenuation, polarizance and retardance vector (normalized Stokes vector) on Poincare sphere, evaluated from Mueller matrix of optically anisotropic stromal region of cervical tissues, is presented for cervical precancer detection and its staging. This reveals that the changes in the polarization states shown by these normalized Stokes vectors corresponds to the degradation of linearly arranged collagen fibers, breakage of the collagen cross links in the stromal region and change in the density of scattering sites when cervical cancer evolves. The distinct nature of real and imaginary parts of the refractive index for linear, linear-45 and circular polarization from the optically anisotropic stromal region underscore the various polarization structures of the connective tissue region which get modified during the pathological changes. It has been found that versatility of these vectors for normal and precancerous cervical tissue of various grades may be utilized as a key distinction for qualitative staging of cervical precancer tissue. Quantitative classification of precancerous stages of cervical precancer has been determined with 95%-100% sensitivity and 93%-100% specificity through the evaluation of linear and circular diattenuation, linear polarizance and linear birefringence from the components of the respective vectors.

The polarized Sun and sky radiometer SSARA: design, calibration, and application for ground-based aerosol remote sensing

Abstract. Recently, polarimetry has been used to enhance classical photometry to infer aerosol optical properties, as polarized radiation contains additional information about the particles. Therefore, we have equipped the Sun–sky automatic radiometer (SSARA) with polarizer filters to measure linearly polarized light at 501.5 nm. We describe an improved radiometric and polarimetric calibration method, which allows us to simultaneously determine the linear polarizers' diattenuation and relative orientation with high accuracy (0.002 and 0.1∘, respectively). Furthermore, we employed a new calibration method for the alt-azimuthal mount capable of correcting the instrument's pointing to within 32 arcmin. So far, this is limited by the accuracy of the Sun tracker. Both these methods are applicable to other Sun and sky radiometers, such as the Cimel CE318-DP instruments used in the AErosol RObotic NETwork (AERONET). During the A-LIFE (Absorbing aerosol layers in a changing climate: aging, LIFEtime and dynamics) field campaign in April 2017, SSARA collected 22 d of data. Here, we present two case studies. The first demonstrates the performance of an aerosol retrieval from SSARA observations under partially cloudy conditions. In the other case, a high aerosol load due to a Saharan dust layer was present during otherwise clear-sky conditions.

Optimization of fast spectrally encoded Mueller polarimeters for real-time monitoring.

In this paper, we report a generalized theoretical framework on spectrally encoded polarimeters to display in real time both linear and circular retardance as well as linear and circular diattenuation on the basis of a recent experimental work detailed in Sci. Rep.9, 3972 (2019)SRCEC32045-232210.1038/s41598-019-40467-z. The considered polarimeters use a broadband light source and wavelength-dependent retarders whose thicknesses are selected to guarantee minimal noise propagation and reduced data processing for real-time display of pure polarimetric effects.

Polarization properties of silver nanowire/polymer composite films: diattenuation, retardance and depolarization

Polarization properties of silver nanowire (AgNW)/polymer composite films are investigated by spectroscopic polarimetry, with special attention to their potential application as the transparent conductive electrode of touch screen devices. The analysis of the Mueller matrix decomposition for preferentially oriented AgNW networks shows linear diattenuation and retardance, in addition to depolarization due to the scattering of light by AgNWs. Diattenuation, retardance and depolarization increases with increasing loading amounts of AgNWs. Conversely, depolarization decreases when the diameter of the AgNWs decreases. These polarization properties have an impact on the polarization state of the transmitted light. When applied to a model of liquid crystal display (LCD) with in-cell touch screen (AgNW composite film is placed between crossed linear polarizers), this results in light leakage. However, such leakage (transmittance) can be reduced to 7 × 10−4% by using AgNWs with a diameter of less than or equal to 23 nm, in a film with a sheet resistance of 50Ω/sq, and by aligning the optic axis of the composite film with the transmission axis of the polarizers.

Optical characterization of porcine articular cartilage using a polarimetry technique with differential Mueller matrix formulism.

A method is proposed for characterizing the optical properties of articular cartilage sliced from a pig's thighbone using a Stokes-Mueller polarimetry technique. The principal axis angle, phase retardance, optical rotation angle, circular diattenuation, diattenuation axis angle, linear diattenuation, and depolarization index properties of the cartilage sample are all decoupled in the proposed analytical model. Consequently, the accuracy and robustness of the extracted results are improved. The glucose concentration, collagen distribution, and scattering properties of samples from various depths of the articular cartilage are systematically explored via an inspection of the related parameters. The results show that the glucose concentration and scattering effect are both enhanced in the superficial region of the cartilage. By contrast, the collagen density increases with an increasing sample depth.

Submicron scale tissue multifractal anisotropy in polarized laser light scattering

The spatial fluctuations of the refractive index within biological tissues exhibit multifractal anisotropy, leaving its signature as a spectral linear diattenuation of scattered polarized light. The multifractal anisotropy has been quantitatively assessed by the processing of relevant Mueller matrix elements in the Fourier domain, utilizing the Born approximation and subsequent multifractal analysis. The differential scaling exponent and width of the singularity spectrum appear to be highly sensitive to the structural multifractal anisotropy at the micron/sub-micron length scales. An immediate practical use of these multifractal anisotropy parameters was explored for non-invasive screening of cervical precancerous alterations ex vivo, with the indication of a strong potential for clinical diagnostic purposes.

Forward scattering of polarized light from a turbid slab: theory and Monte Carlo simulations.

It is proved that if reciprocity and mirror symmetry hold for single scattering by a particle, they also hold for multiple scattering in turbid slab media. Monte Carlo simulations generate a reduced effective Mueller matrix for forward scattering, which satisfies reciprocity and mirror symmetry, but satisfies only reciprocity if the medium contains chiral components. The scattering matrix was factorized by using the Lu-Chipman polar decomposition, which affords the polarization parameters as a function of the radial distance from the center. The depolarization coefficients decrease with increasing distance, whereas the scattering-induced linear diattenuation and retardance become larger in the middle-distance range. The optical rotation for a chiral medium increases with increasing distance.

Monochromatic measurements of the JPSS-1 VIIRS polarization sensitivity.

Polarization sensitivity is a critical property that must be characterized for spaceborne remote sensing instruments designed to measure reflected solar radiation. Broadband testing of the first Joint Polar-orbiting Satellite System (JPSS-1) Visible Infrared Imaging Radiometer Suite (VIIRS) showed unexpectedly large polarization sensitivities for the bluest bands on VIIRS (centered between 400 and 600 nm). Subsequent ray trace modeling indicated that large diattenuation on the edges of the bandpass for these spectral bands was the driver behind these large sensitivities. Additional testing using the National Institute of Standards and Technology's Traveling Spectral Irradiance and Radiance Responsivity Calibrations Using Uniform Sources was added to the test program to verify and enhance the model. The testing was limited in scope to two spectral bands at two scan angles; nonetheless, this additional testing provided valuable insight into the polarization sensitivity. Analysis has shown that the derived diattenuation agreed with the broadband measurements to within an absolute difference of about 0.4% and that the ray trace model reproduced the general features of the measured data. Additionally, by deriving the spectral responsivity, the linear diattenuation is shown to be explicitly dependent on the changes in bandwidth with polarization state.