Showing papers on "Light scattering published in 2022"
TL;DR: In this paper , a method that takes into account light scattering in the resin prior to computing projection patterns is proposed, and it is experimentally demonstrated that implementation of this correction is critical when printing objects whose size exceeds the scattering mean free path.
Abstract: 3D printing has revolutionized the manufacturing of volumetric components and structures in many areas. Several fully volumetric light‐based techniques have been recently developed thanks to the advent of photocurable resins, promising to reach unprecedented short print time (down to a few tens of seconds) while keeping a good resolution (around 100 μm). However, these new approaches only work with homogeneous and relatively transparent resins so that the light patterns used for photo‐polymerization are not scrambled along their propagation. Herein, a method that takes into account light scattering in the resin prior to computing projection patterns is proposed. Using a tomographic volumetric printer, it is experimentally demonstrated that implementation of this correction is critical when printing objects whose size exceeds the scattering mean free path. To show the broad applicability of the technique, functional objects of high print fidelity are fabricated in hard organic scattering acrylates and soft cell‐laden hydrogels (at 4 million cells mL−1). This opens up promising perspectives in printing inside turbid materials with particular interesting applications for bioprinting cell‐laden constructs.
30 citations
TL;DR: In this article , a modified Cornet model for light transmission in microalgal suspensions is established by comprehensively considering cell concentrations, pigment components, and light spectra, which better fits experimental data with a higher adjusted R2 than the model that is based only on cell concentration.
26 citations
TL;DR: In this article , the authors summarize the amazing power and fundamental limits of controlling multiple light scattering, which lay the physical foundation to harness multiply-scattered light for imaging and communication purposes.
Abstract: The main obstacle for optical imaging or for sending information through turbid media such as paint, clouds and biological tissue is the random scattering of light. Owing to its immense complexity, the process of multiple scattering has long been described by the diffusion equation, which ignores the interference of scattered light. Recent developments in optical wavefront shaping and phase recording techniques have enabled the breaking of the diffusion limit and the control of coherent light transport in complex media, including strongly scattering tissues and multimode optical fibres with random mode mixing. Great advances have been made in focusing and controlling the transmission of light through such complex systems and in performing various tasks behind them, such as optical micro-manipulation. Here, we summarize the amazing power and the fundamental limits of controlling multiple light scattering, which lay the physical foundation to harness multiply-scattered light for imaging and communication purposes. Connections to practical applications are illustrated, in particular in those areas covered in the companion articles in this issue. Multiple scattering fundamentally complicates the task of sending light through turbid media, as many applications require. This Review summarizes the theoretical framework and experimental techniques to understand and control these processes.
25 citations
TL;DR: Zhang et al. as discussed by the authors proposed a novel underwater image restoration method based on information distribution and light scattering prior, which can effectively remove the color cast and increase contrast in underwater images.
22 citations
TL;DR: In this paper , the advantages, performance and limitations of light-sheet fluorescence microscopy (LSFM) have been discussed, ranging from fully optical solutions to entirely digital post-processing approaches.
Abstract: In recent years, light-sheet fluorescence microscopy (LSFM) has found a broad application for imaging of diverse biological samples, ranging from sub-cellular structures to whole animals, both in-vivo and ex-vivo, owing to its many advantages relative to point-scanning methods. By providing the selective illumination of sample single planes, LSFM achieves an intrinsic optical sectioning and direct 2D image acquisition, with low out-of-focus fluorescence background, sample photo-damage and photo-bleaching. On the other hand, such an illumination scheme is prone to light absorption or scattering effects, which lead to uneven illumination and striping artifacts in the images, oriented along the light sheet propagation direction. Several methods have been developed to address this issue, ranging from fully optical solutions to entirely digital post-processing approaches. In this work, we present them, outlining their advantages, performance and limitations.
20 citations
TL;DR: In this paper , a physical-optical model of the PMS was developed to estimate light intensity on the photodiode, accounting for angular truncation of the volume scattering function as a function of particle size.
Abstract: Abstract. The Plantower PMS5003 sensors (PMS) used in the PurpleAir monitor PA-II-SD configuration (PA-PMS) are equivalent to cell-reciprocal nephelometers using a 657 nm perpendicularly polarized light source that integrates light scattering from 18 to 166∘. Yearlong field data at the National Oceanic and Atmospheric Administration's (NOAA) Mauna Loa Observatory (MLO) and Boulder Table Mountain (BOS) sites show that the 1 h average of the PA-PMS first size channel, labeled “> 0.3 µm” (“CH1”), is highly correlated with submicrometer aerosol scattering coefficients at the 550 and 700 nm wavelengths measured by the TSI 3563 integrating nephelometer, from 0.4 to 500 Mm−1. This corresponds to an hourly average submicrometer aerosol mass concentration of approximately 0.2 to 200 µg m−3. A physical–optical model of the PMS is developed to estimate light intensity on the photodiode, accounting for angular truncation of the volume scattering function as a function of particle size. The model predicts that the PMS response to particles > 0.3 µm decreases relative to an ideal nephelometer by about 75 % for particle diameters ≥ 1.0 µm. This is a result of using a laser that is polarized, the angular truncation of the scattered light, and particle losses (e.g., due to aspiration) before reaching the laser. It is shown that CH1 is linearly proportional to the model-predicted intensity of the light scattered by particles in the PMS laser to its photodiode over 4 orders of magnitude. This is consistent with CH1 being a measure of the scattering coefficient and not the particle number concentration or particulate matter concentration. The model predictions are consistent with data from published laboratory studies which evaluated the PMS against a variety of aerosols. Predictions are then compared with yearlong fine aerosol size distribution and scattering coefficient field data at the BOS site. Field data at BOS confirm the model prediction that the ratio of CH1 to the scattering coefficient would be highest for aerosols with median scattering diameters < 0.3 µm. The PMS detects aerosols smaller than 0.3 µm diameter in proportion to their contribution to the scattering coefficient. The results of this study indicate that the PMS is not an optical particle counter and that its six size fractions are not a meaningful representation of particle size distribution. The relationship between the PMS 1 h average CH1 and bsp1, the scattering coefficient in Mm−1 due to particles below 1 µm aerodynamic diameter, at wavelength 550 nm, is found to be bsp1 = 0.015 ± 2.07 × 10−5 × CH1, for relative humidity below 40 %. The coefficient of determination r2 is 0.97. This suggests that the low-cost and widely used PA monitors can be used to measure and predict the submicron aerosol light scattering coefficient in the mid-visible nearly as well as integrating nephelometers. The effectiveness of the PA-PMS to serve as a PM2.5 mass concentration monitor is due to both the sensor behaving like an imperfect integrating nephelometer and the mass scattering efficiency of ambient PM2.5 aerosols being roughly constant.
15 citations
TL;DR: In this article , the optical fiber is made as transparent as possible and nanoparticles are inserted into optical fibres, contrary to this quest for transparency, despite the fact that nanoparticles have been inserted in optical fiber for twenty years.
Abstract: Since its first creation, glass has always fascinated with its optical properties, its ability to let light through without being invisible. One of the most spectacular achievements of optical glass is the optical fiber for which considerable work has been done to make it as transparent as possible. However, for twenty years, contrary to this quest for transparency, nanoparticles have been inserted into optical fibres. First designed to develop new lasers and amplifiers, the lowest possible particle-induced light scattering then sought has for the last four years, on the contrary, been exacerbated in order to develop new sensors.
13 citations
12 citations
TL;DR: In this paper , the authors developed polyclonal antibody-functionalized spherical gold nanoparticle biosensors as well as the influence of the nanoparticle sizes on the immunoassay response to detect the SARS-CoV-2 spike protein.
12 citations
TL;DR: In this paper , an all-dielectric quasi-three-dimensional subwavelength structure, consisting of multilayer films and metagratings, was proposed to achieve perfect anomalous reflections at optical frequencies.
Abstract: Reflecting light to a predetermined nonspecular direction is an important ability of metasurfaces, which is the basis for a wide range of applications (e.g., beam steering/splitting and imaging). However, anomalous reflection with 100% efficiency has not been achieved at optical frequencies yet, because of losses and/or insufficient nonlocal control of light waves. Here, we propose an all-dielectric quasi-three-dimensional subwavelength structure, consisting of multilayer films and metagratings, to achieve perfect anomalous reflections at optical frequencies. A complex multiple scattering process was stimulated by effectively coupling different Bloch waves and propagating waves, thus offering the metasystem the desired nonlocal control on light waves required by perfect anomalous reflections. Two perfect anomalous reflectors were demonstrated to reflect normally incident 1550-nm light to the 40°/75° directions with absolute efficiencies of 99%/99% in design (98%/88% in experiment). Our results pave the way toward realizing optical metadevices with desired high efficiencies in realistic applications.
11 citations
TL;DR: Elastic light scattering (ELS) from single micron-sized particles has been used as a fast, non-destructive diagnostic tool in life science, physics, chemistry, climatology, and astrophysics as discussed by the authors .
Abstract: Elastic light scattering (ELS) from single micron-sized particles has been used as a fast, non-destructive diagnostic tool in life science, physics, chemistry, climatology, and astrophysics. Due to the large scattering cross-section, ELS can be used to find trace amounts of suspect particles such as bioaerosols among complex, diverse atmospheric aerosols, based on single-particle interrogation. In this article, we briefly summarized the main computational models and instrumentation developed for ELS, then reviewed how properties like particle size, refractive index, degree of symmetry, and surface roughness, in addition to packing density, shape of primary particles in an aggregate, and special helix structures in compositions can be determined from ELS measurements. Meanwhile, we emphasize on how these parameters obtained from ELS measurements can be used for bioaerosol detection, characterization, and discrimination from atmospheric aerosol particles using different classification algorithms.
TL;DR: In this article , the current state and sources of brown carbon (BrC) in Mexico were investigated and the authors elucidated the current and source of BrC in Mexico, which has significant impacts on climate forcing and air quality.
Abstract: Brown carbon (BrC) is a component of particulate matter which has significant impacts on climate forcing and air quality. To elucidate the current state and sources of BrC in Mexico...
TL;DR: In this article , a lab-on-a-chip device for the rapid detection of P. aeruginosa based on immunomagnetic separation, optical scattering, and machine learning is presented.
TL;DR: In this paper, a lab-on-a-chip device for the rapid detection of P. aeruginosa based on immunomagnetic separation, optical scattering, and machine learning is presented.
TL;DR: In this paper , a signal-to-noise ratio enhancement of 3.4 dB is reported by using twomode intensity-difference squeezed light generated with the four-wave mixing process in atomic rubidium vapor.
Abstract: Brillouin microscopy is an emerging label-free imaging technique used to assess local viscoelastic properties. Quantum-enhanced stimulated Brillouin scattering is demonstrated using low power continuous-wave lasers at 795 nm. A signal-to-noise ratio enhancement of 3.4 dB is reported by using two-mode intensity-difference squeezed light generated with the four-wave mixing process in atomic rubidium vapor. The low optical power and the excitation wavelengths in the water transparency window have the potential to provide a powerful bio-imaging technique for probing mechanical properties of biological samples prone to phototoxicity and thermal effects. The performance enhancement affordable through the use of quantum light may pave the way for significantly improved sensitivity that cannot be achieved classically. The proposed method for utilizing squeezed light for enhanced stimulated Brillouin scattering can be easily adapted for both spectroscopic and imaging applications in biology.
TL;DR: In this article , sustainable and modifiable regenerated cellulose films were produced via an ionic liquid process and combined with the excellent properties of titanium dioxide (TiO2) particles to prepare highly light-scattering and UV-absorbing composite film materials.
TL;DR: In this article , a two-dimensional resonator encircled by gain metasurfaces incorporating negative- resistance components was designed to overcome the single-channel scattering limit and demonstrate that the scattering cross section exceeds the single channel limit by more than 40-fold.
Abstract: A long-held tenet in physics asserts that particles interacting with light suffer from a fundamental limit to their scattering cross section, referred to as the single-channel scattering limit. This notion, appearing in all one, two, and three dimensions, severely limits the interaction strength between all types of passive resonators and photonic environments and thus constrains a plethora of applications in bioimaging, sensing, and photovoltaics. Here, we propose a route to overcome this limit by exploiting gain media. We show that when an excited resonance is critically coupled to the desired scattering channel, an arbitrarily large scattering cross section can be achieved in principle. From a transient analysis, we explain the formation and relaxation of this phenomenon and compare it with the degeneracy-induced multi-channel superscattering, whose temporal behaviors have been usually overlooked. To experimentally test our predictions, we design a two-dimensional resonator encircled by gain metasurfaces incorporating negative- resistance components and demonstrate that the scattering cross section exceeds the single- channel limit by more than 40-fold. Our findings verify the possibility of stronger scattering beyond the fundamental scattering limit and herald a novel class of light-matter interactions enabled by gain metasurfaces.
TL;DR: In this paper, an optical sensor with ratiometric and turn-off dual modes is constructed to detect H2O2 and glucose based on blue fluorescent carbon dots (CDs) and MnO2 nanosheets with great ability of fluorescence quenching and scattering.
TL;DR: In this paper , the authors compared the distribution of scattered light intensity in a GPU-accelerated Monte Carlo simulation of photon transport through turbid media, focusing on the validation of the online software Multi-Scattering.
Abstract: This article, Part II of an article series on GPU-accelerated Monte Carlo simulation of photon transport through turbid media, focuses on the validation of the online software Multi-Scattering. While Part I detailed the implementation of the computational model, simulated and experimental results are now compared for the distribution of the scattered light intensity. The scattering phantoms prepared here are aqueous dispersions of polystyrene microspheres of diameter D = 0.5, 2 and 5 μm and at various concentrations, resulting in optical depth ranging from OD = 1 to 17.5. The Lorenz-Mie scattering phase functions used in the simulations have been verified experimentally at low particle concentrations by analyzing the angular light intensity distribution at the Fourier plane of a collecting lens. The validation approach herein accounts for the specific light collection and image formation by the camera. The front and side surfaces of the medium are imaged and the corresponding light intensity distributions are compared qualitatively and quantitatively. It is concluded that the model enables reliable simulations over the tested parameters, offering predictive simulations of transmitted intensities with a mean relative error ≤~19% over the full range. The online software is available at: https://multi-scattering.com/.
TL;DR: In this article , the authors review and summarise recent achievements in the emergent field of acoustic frequency combs (AFCs), including phononic FCs and relevant acousto-optical, Brillouin light scattering and Faraday wave-based techniques that have enabled the development of phonon lasers, quantum computers and advanced vibration sensors.
Abstract: Frequency combs (FCs)—spectra containing equidistant coherent peaks—have enabled researchers and engineers to measure the frequencies of complex signals with high precision, thereby revolutionising the areas of sensing, metrology and communications and also benefiting the fundamental science. Although mostly optical FCs have found widespread applications thus far, in general FCs can be generated using waves other than light. Here, we review and summarise recent achievements in the emergent field of acoustic frequency combs (AFCs), including phononic FCs and relevant acousto-optical, Brillouin light scattering and Faraday wave-based techniques that have enabled the development of phonon lasers, quantum computers and advanced vibration sensors. In particular, our discussion is centred around potential applications of AFCs in precision measurements in various physical, chemical and biological systems in conditions where using light, and hence optical FCs, faces technical and fundamental limitations, which is, for example, the case in underwater distance measurements and biomedical imaging applications. This review article will also be of interest to readers seeking a discussion of specific theoretical aspects of different classes of AFCs. To that end, we support the mainstream discussion by the results of our original analysis and numerical simulations that can be used to design the spectra of AFCs generated using oscillations of gas bubbles in liquids, vibrations of liquid drops and plasmonic enhancement of Brillouin light scattering in metal nanostructures. We also discuss the application of non-toxic room-temperature liquid–metal alloys in the field of AFC generation.
TL;DR: In this paper, the authors present an updated theoretical background of forward and inverse analysis for particle size distribution measurements of disperse samples, in particular, both well-tried and recent methods for analytical and numerical treatment of measurement data inversion.
TL;DR: In this article , an optical sensor with ratiometric and turn-off dual modes is constructed to detect H2O2 and glucose based on blue fluorescent carbon dots (CDs) and MnO2 nanosheets with great ability of fluorescence quenching and scattering.
TL;DR: In this paper , the authors proposed a method to identify and identify the 2 µm and 5 µm sized particles using a laser light scattering, which is based on measuring forward light scattering from the particles and then classifying the acquired data using support vector machines.
TL;DR: In this paper , high transparent polyisocyanurate-polyurethane (PUR-PIR) aerogels were synthesized, and their optical properties were studied in detail.
Abstract: Highly transparent polyisocyanurate–polyurethane (PUR–PIR) aerogels were synthesized, and their optical properties were studied in detail. After determining the density and structural parameters of the manufactured materials, we analyzed their optical transmittance. It was demonstrated that the catalyst content used to produce the aerogels can be employed to tune the internal structure and optical properties. The results show that the employment of lower catalyst amounts leads to smaller particles forming the aerogel and concomitantly to higher transmittances, which reach values of 85% (650 nm) due to aerogel particles acting as scattering centers. Thus, it was found that the lower this size, the higher the transmittance. The effect of the sample thickness on the transmittance was studied through the Beer–Lambert law. Finally, the scattering mechanisms involved in the light attenuation were systematically evaluated by measuring a wide range of light wavelengths and determining the transition between Rayleigh and Mie scattering when the particles were larger. Therefore, the optical properties of polyurethane aerogels were studied for the first time, opening a wide range of applications in building and energy sectors such as glazing windows.
TL;DR: In this article , light penetration in skeletal muscle samples has been improved via a combination of physical and photothermal approaches, and optical microscopic images of the samples show contrast improvement due to the light penetration enhancement.
Abstract: Optical diagnostic methods are still suffering from relatively low resolution due to low light penetration produced by the multiple scattering properties of biological tissues. Light scattering reduction can improve various biomedical diagnostic and therapeutic applications. Therefore, the optical clearing approach was introduced to reduce light scattering and improve its penetration in soft and hard tissues. Many optical clearing protocols could be applied depending on the physical properties of the inspected tissue. These protocols are classified into physical, chemical, photochemical/photothermal, and compression. In the present study, light penetration in skeletal muscle samples has been improved via a combination of physical and photothermal approaches. Bovine skeletal muscle samples have been exposed to IR laser radiation (at 1064 nm) before immersion in 99% glycerol, providing a reduction in the immersing time and increasing the efficacy of the clearing process. Additionally, spectrochemical changes in the studied samples were investigated via laser-induced fluorescence technique before and after laser exposure and glycerol immersion. Tissue collimated transmittance has been monitored at different immersion times. A significant increase shows up, especially after laser exposure revealing the improvement in light penetration. Moreover, optical microscopic images of the samples show contrast improvement due to the light penetration enhancement.
TL;DR: In this article , a review is devoted to a discussion of new (and often unexpected) aspects of the old problem of elastic light scattering by small metal particles, whose size is comparable to or smaller than the thickness of the skin layer.
Abstract: Abstract This review is devoted to a discussion of new (and often unexpected) aspects of the old problem of elastic light scattering by small metal particles, whose size is comparable to or smaller than the thickness of the skin layer. The main focus is on elucidating the physical grounds for these new aspects. It is shown that, in many practically important cases, the scattering of light by such particles, despite their smallness, may have almost nothing in common with the Rayleigh scattering. So-called anomalous scattering and absorption, as well as Fano resonances, including unconventional (associated with the excitation of longitudinal electromagnetic oscillations) and directional Fano resonances, observed only at a small solid angle, are discussed in detail. The review contains a Mathematical Supplement, which includes a summary of the main results of the Mie theory and a discussion of some general properties of scattering coefficients. In addition to being of purely academic interest, the phenomena considered in this review can find wide applications in biology, medicine, pharmacology, genetic engineering, imaging of ultra-small objects, ultra-high-resolution spectroscopy, information transmission, recording, and processing, as well as many other applications and technologies.
TL;DR: In this paper , a modified iterative algorithm with an interpretable constraint on the optical transfer function (OTF) was employed to solve the inverse problem of noninvasive scattering imaging.
Abstract: We experimentally investigate image reconstruction through a scattering medium under white-light illumination. To solve the inverse problem of noninvasive scattering imaging, a modified iterative algorithm is employed with an interpretable constraint on the optical transfer function (OTF). As a result, a sparse and real object can be retrieved whether it is illuminated with a narrowband or broadband light. Compared with the well-known speckle correlation technique (SCT), the proposed method requires no restrictions on the speckle autocorrelation and shows a potential advantage in scattering imaging.
TL;DR: In this article , a polarization descattering imaging method was developed using the Mueller matrix, which in turn derived a depolarization (Dep) index from the Mueller matrices to characterize scattering media by estimating the transmittance map by combining a developed optimal function.
Abstract: Polarization underwater imaging is of great potential to target detection in turbid water. Typical methods are challenged by the requirement on degrees of polarization (DoPs) of both target light and backscattering. A polarization descattering imaging method was developed using the Mueller matrix, which in turn derived a depolarization (Dep) index from the Mueller matrix to characterize scattering media by estimating the transmittance map by combining a developed optimal function. By quantifying light attenuation with the transmittance map, a clear vision of targets can be recovered. Only using the information of scattering media, the underwater vision under diverse water turbidity was enhanced by the results of experimental data.
TL;DR: Brillouin scattering has been extensively used to measure various elementary excitations and quasi-elastic scattering in the gigahertz range between 0.1 and 1000 GHz as mentioned in this paper .
Abstract: L. Brillouin predicted inelastic light scattering by thermally excited sound waves in 1922. Brillouin scattering is a non-contact and non-destructive method to measure sound velocity and attenuation. It is possible to investigate the elastic properties of gases, liquids, glasses, and crystals. Various kinds of phase transitions, i.e., liquid–glass transitions, crystallization, polymorphism, and denaturation have been studied by changing the temperature, pressure, time, and external fields such as the electric, magnetic, and stress fields. Nowadays, Brillouin scattering is extensively used to measure various elementary excitations and quasi-elastic scattering in the gigahertz range between 0.1 and 1000 GHz. A brief history, spectroscopic methods, and Brillouin scattering studies in materials science on ferroelectric materials, glasses, and proteins are reviewed.
TL;DR: In this article, a polarization descattering imaging method was developed using the Mueller matrix, which in turn derived a depolarization (Dep) index from the Mueller matrices to characterize scattering media by estimating the transmittance map by combining a developed optimal function.
Abstract: Polarization underwater imaging is of great potential to target detection in turbid water. Typical methods are challenged by the requirement on degrees of polarization (DoPs) of both target light and backscattering. A polarization descattering imaging method was developed using the Mueller matrix, which in turn derived a depolarization (Dep) index from the Mueller matrix to characterize scattering media by estimating the transmittance map by combining a developed optimal function. By quantifying light attenuation with the transmittance map, a clear vision of targets can be recovered. Only using the information of scattering media, the underwater vision under diverse water turbidity was enhanced by the results of experimental data.