Photon Correlation Research Articles

Characterization of Defocused Coherent Imaging Systems with Periodic Objects.

Recent advancements in quantum and quantum-inspired imaging techniques have enabled high-resolution 3D imaging through photon correlations. These techniques exhibit reduced degradation of image resolution for out-of-focus samples compared to conventional methods (i.e., intensity-based incoherent imaging). A key advantage of these correlation-based approaches is their independence from the system numerical aperture (NA). Interestingly, both improved resolution of defocused images and NA-independent scaling are linked to the spatial coherence of light. This suggests that while correlation measurements exploit spatial coherence, they are not essential for achieving this imaging advantage. This discovery has led to the development of optical systems that achieve similar performance by using spatially coherent illumination and relying on intensity measurements: direct 3D imaging with NA-independent resolution was recently demonstrated in a correlation-free setup using LED light. Here, we explore the physics behind the enhanced performance of defocused coherent imaging, showing that it arises from the modification of the sample's spatial harmonic content due to diffraction, unlike the blurring seen in conventional imaging. The results we present are crucial for understanding the implications of the physical differences between coherent and incoherent imaging, and are expected to pave the way for the practical application of the discovered phenomena.

Investigation of Alginate-Chitosan nanoparticles As a Drug Carrier for Levothyroxine

Background: This study synthesized alginate-chitosan nanoparticles (ALG/CS NPs) as nanocarriers for the hydrophobic drug levothyroxine and investigated their nanoparticle size. Objectives: Alginate-chitosan nanoparticles were prepared through ionotropic gelation of the chitosan core followed by complexation with alginate. Methods: The nanoparticles were characterized for particle morphology, size, and polydispersity index using transmission electron microscopy (TEM) and photon correlation spectroscopy. Results: Alginate-chitosan nanoparticles were found in a nanoscale spherical shape with an average particle size of 90 - 110 nm. Results indicated that the release mechanism depends on dissolution in the initial hours. For levothyroxine release from ALG/CS NPs, the Higuchi model fits better than the other models. The drug release kinetics were investigated, and the release kinetics data were best fitted with the Higuchi model. Conclusions: Levothyroxine was released mainly in the first 20 hours at an average rate of up to 78% at pH 7.4.

Dynamic X-ray Coherent Diffraction Analysis: Bridging the Time Scales between Imaging and Photon Correlation Spectroscopy.

The advent of diffraction limited sources and developments in detector technology opens up new possibilities for the study of materials in situ and operando. Coherent X-ray diffraction techniques such as coherent X-ray diffractive imaging (CXDI) and X-ray photon correlation spectroscopy (XPCS) are capable for this purpose and provide complementary information, although due to signal-to-noise requirements, their simultaneous demonstration has been limited. Here, we demonstrate a strategy for the simultaneous use of CXDI and XPCS to study in situ the Brownian motion of colloidal gold nanoparticles of 200 nm diameter suspended in a glycerol-water mixture. We visualize the process of agglomeration, examine the spatiotemporal space accessible with the combination of techniques, and demonstrate CXDI with 22 ms temporal resolution.

Decomposition of mixed DMPC-aescin vesicles to bicelles is linked to the lipid's main phase transition: A direct evidence by using chain-deuterated lipid

This work investigates the conversion of bicelles into larger sheets or closed vesicles upon dilution and temperature increase for a system composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the saponin aescin. Due to its peculiar amphiphilic character, aescin is able to decompose DMPC bilayers into smaller, rim-stabilized bicelles. Aspects of the transition process are analyzed in an aescin content- and temperature-dependent manner by photon correlation spectroscopy (PCS), turbidimetry and small-angle neutron scattering (SANS). Both the conversion of bicelles into vesicles induced by temperature increase and the decomposition process upon cooling are presumably related to the main phase transition temperature Tm of DMPC. Therefore, not only conventional DMPC, but also chain-deuterated d54-DMPC was used due to its significantly lower Tm-value compared to the conventional DMPC. It will be demonstrated that the reconversion of vesicle structures (present at low aescin content) into bicelles shows a strong hysteresis effect whereas this is not observed for the reconversion at high aescin amounts, at which for high temperature still bicelle structures are present. The results indicate formation of a trapped state, correlated with the lipid's Tm and the decomposition of vesicles into bicelles is only possible if the lipid membrane entirely adopts the rigid phase state.

Nonequilibrium energy transport and nonclassical correlations of photons in a two-mode circuit quantum electrodynamic system

Nonequilibrium energy transport and nonclassical correlations of photons in a two-mode circuit quantum electrodynamic system

Development and in vitro characterization of new carnosine-loaded liposomal formulations.

Carnosine is an endogenous dipeptide characterized by a multimodal mechanism of action. However, its clinical potential is limited by serum and cytosolic carnosinases, which significantly reduce its bioavailability. Based on that, different research groups have worked on the development of new strategies able not only to prevent its rapid metabolization but also to improve its distribution and specific targeting. In the present study, the development and in vitro characterization of new liposomal formulations loaded with carnosine are described. Nanoliposomes, produced through Thin-Layer Hydration followed by Extrusion method, were first investigated for their physicochemical stability. Photon correlation spectroscopy and electrophoretic light scattering, assessing the stability of the formulations, showed a strong homogeneity-oriented tendency for up to two months. Particle size, polydispersity index, and zeta potential were determined through dynamic light scattering and electrophoretic light scattering, demonstrating an almost neutral charge of the formulation and an effective encapsulation of carnosine. The morphology assessment performed via scanning electron microscopy showed good conformity and polydispersity. Differential scanning calorimetry measurements suggest the ability of carnosine to stabilize the large unilamellar vesicles. Lastly, the newly developed carnosine-loaded liposomal formulations also showed a good safety profile in human microglia.

Berberine-Loaded Bovine Serum Albumin Nanoparticles: Fabrication, Characterization, and Drug Release Evaluation

Abstract Introduction/Objective Introduction: Numerous studies have highlighted the diverse biochemical and pharmacological properties of berberine (BER), including its anti-inflammatory, antioxidant, anticancer, and hypolipidemic effects. Nanoparticles play a crucial role in enhancing drug delivery by providing a larger surface area, facilitating quicker dissolution in the bloodstream. Methods/Case Report Methods: Blank bovine serum albumin nanoparticles (BSA NPs) were prepared using a desolvation process, followed by the fabrication of berberine-loaded BSA nanoparticles (BER-NP). Physicochemical characterization, including particle size and zeta potential, was conducted using a Malvern Zetasizer. The mean particle size and distribution were determined using photon correlation spectroscopy (PCS), and transmission electron microscope (TEM) images were obtained for visualization. Fourier transform infrared (FTIR) spectra and differential scanning calorimetry (DSC) thermograms were recorded to assess drug encapsulation efficiency (EE). Berberine release from BER-NPs was evaluated using dialysis membranes. Results (if a Case Study enter NA) Results: FTIR spectra and DSC thermograms confirmed successful drug loading into the nanoparticles. Encapsulation efficiency was determined by UV absorption spectroscopy, revealing high efficiency in the encapsulation process. Dialysis membranes demonstrated controlled release kinetics of berberine from BER-NPs, indicating their potential for targeted drug delivery. Conclusion Conclusion: Berberine-loaded bovine serum albumin nanoparticles exhibit favorable characteristics for drug delivery applications, including enhanced permeation across biological barriers. These nanoparticles hold promise for targeted therapy and combination drug regimens, offering potential benefits for various medical interventions.

On the optical efficiency of collecting scattered radiation or telescopically imaging the measurement area in airborne acoustic pressure evaluations

Photon correlation is an optical method for calculating acoustic pressures through particle velocity measurements, involving the intersection of two focused Gaussian beams forming an interference fringe pattern. Particles within this measurement region exhibit sinusoidal motion as a result of a propagating acoustic pressure wave over the fringes, consequently scattering photons. This scattered radiation is then collected and processed to determine the particle velocity and then the acoustic pressure. In order to analyse the efficiency of the optical collection system, decoupled optical delivery configurations were implemented. In this case, instead of relying on particles moving over static fringes, moving fringes can be made to pass over an apparently static particle. To simulate this effect, a single laser beam can be modulated with a 3-D printed pattern simulating sinusoidal particle motion across fringes. Having established this alternative delivery system, suitable optical collection systems can be implemented, so that their efficiency can be analysed and assessed. This paper reports on the details of two such collection systems; analysing spherically propagated radiation and telescopically capturing the measurement area respectively.

Cross-comparison of the optical and acoustical calibration methods for microphones based on microelectromechanical system technologies

Calibration methods and associated international standards in airborne acoustics have enabled national metrology institutes to establish and maintain a fully defined traceability chain for designated laboratories and end users of microphones. However, such microphones need to be reciprocal, of condenser type and of specific dimensions; this, in effect, does not allow for the calibration of alternative existing sensor technologies and creates a further obstacle for the calibration of emerging technologies. An example relates to microphones based on microelectromechanical systems which are an integral part of a wide range of electronic devices; yet, there is no established calibration traceability chain other than methods employed by manufacturers. From a metrological perspective, new calibration methods that can accommodate microphones regardless of their size, reciprocal nature and utilised technology must be developed and subsequently standardised and adopted. This paper discusses the optical calibration method based on free field photon correlation and the acoustical calibration methods based on pressure comparison and free field substitution. These approaches can provide traceability to the international measurement standard system for novel types of microphones, and the measurement results showed themselves to be consistent. Based on this study, the possibility of expanding the new standard system was investigated.

Turbulence effects mitigation for twin-photons generated by high order transverse modes

Turbulence presents challenges for free-space light-based protocols. In this work, we investigated the effect of turbulence on the correlations of twin photons prepared in Spontaneous Parametric Down Conversion (SPDC) by a pump beam with different transverse modes. We demonstrate that the strategy of coordinate inversion for mitigating turbulence-induced distortions on transverse coincidence profiles is effective for twin photons generated by HG/LG modes. The conservation of orbital angular momentum in SPDC enables us to encode information in the transverse degrees of freedom of the down-converted photon pairs. This information can have its correlation protected by the coordinate inversion technique against weak turbulence effects in free-space links.

Distinguishing Protein Corona from Nanoparticle Aggregate Formation in Complex Biological Media Using X-ray Photon Correlation Spectroscopy.

In biological systems, nanoparticles interact with biomolecules, which may undergo protein corona formation that can result in noncontrolled aggregation. Therefore, comprehending the behavior and evolution of nanoparticles in the presence of biological fluids is paramount in nanomedicine. However, traditional lab-based colloid methods characterize diluted suspensions in low-complexity media, which hinders in-depth studies in complex biological environments. Here, we apply X-ray photon correlation spectroscopy (XPCS) to investigate silica nanoparticles (SiO2) in various environments, ranging from low to high complex biological media. Interestingly, SiO2 revealed Brownian motion behavior, irrespective of the complexity of the chosen media. Moreover, the SiO2 surface and media composition were tailored to underline the differences between a corona-free system from protein corona and aggregates formation. Our results highlighted XPCS potential for real-time nanoparticle analysis in biological media, surpassing the limitations of conventional techniques and offering deeper insights into colloidal behavior in complex environments.

Characterization of the α-relaxation and gel-like dynamics in mixed network forming (GeO2)x(NaPO3)100-x glass melts by photon correlation spectroscopy

Dynamic light scattering investigations of the α-relaxation in network-forming (GeO2)x(NaPO3)100-x glass melts is reported for x = 0 to 40 mol% GeO2. Addition of GeO2 results in an increased density of bridging oxygen bonds. This monotonically increases the glass transition temperature but generates complex changes to the glass forming fragility which initially decreases with increasing GeO2 but increases again at higher GeO2 contents. A resolution to this odd fragility behavior is obtained by applying a coarse-graining procedure used previously in sodium germanate melts to arrive at a topological network connectivity for which fragility exhibits a universal dependence. Also observed in the light scattering measurements is a secondary relaxation, several orders of magnitude slower than that of the α-relaxation, which we tentatively attribute to gel-like anomalous diffusion of Ge crosslinks formed between phosphate chains.

Green formulation of Menadione-loaded niosome as a skin-lightening preparation: In vitro/In vivo safety evaluation on Wistar rat

Purpose: In the present research, a green technique (an ultrasonic method) was used to synthesize menadione sodium bisulfite (MSB) niosome (Menasome) which is used to improve dermal delivery and increase anti-melanogenesis activities. Methods: Various cholesterol: surfactant (Chol: Sur) ratios were investigated to optimize the Menasomes. Photon correlation spectroscopy, attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC) were employed to characterize the solid state of MSB in nanoparticle form. Additionally, the optimized formulation was used to investigate ex-vivo skin absorption, in vivo skin irritation, in vitro cell survival, and anti-melanogenesis activity. Results: The results exhibited that increasing cholesterol (Chol) declined the average size of the Menasomes from 653.766±25.171 nm to 298.133±8.823 nm and increased entrapment efficiency 30.237±3.4204% to 83.616±2.550 %. The rat skin permeation study indicated that Menasome gel administered more MSB in dermal layers (439.000±36.190μg/cm2 or 23.827±1.964%) than MSB plain gel (286.200± 22.6μg/cm2 or 15.53±1.227%). In both the in vivo skin irritation test and the in vitro cytotoxicity experiment, the extended-release behavior of the enhanced Menasome demonstrated a minimal side effect profile. Furthermore, optimum Menasome inhibited melanin formation (37.426± 1.644% at 15μM) greater than free MSB (57.383±1.654%) considerably (p <0.05). Furthermore, Menasome 7 prevented L-dopa auto-oxidation in higher levels (95.140±2.439%) than pure MSB solution (83.953±1.629%). Conclusion: According to the study's findings, the prepared Menasome could be employed as a viable nanovehicle for MSB dermal delivery, a promising solution for the management of human hyperpigmentation disorders.

Two photons everywhere.

We discuss two-photon physics, taking for illustration the particular but topical case of resonance fluorescence. We show that the basic concepts of interferences and correlations provide at the two-photon level an independent and drastically different picture than at the one-photon level, with landscapes of correlations that reveal various processes by spanning over all the possible frequencies at which the system can emit. Such landscapes typically present lines of photon bunching and circles of antibunching. The theoretical edifice to account for these features rests on two pillars: (i) a theory of frequency-resolved photon correlations and (ii) admixing classical and quantum fields. While experimental efforts have been to date concentrated on correlations between spectral peaks, strong correlations exist between photons emitted away from the peaks, which are accessible only through multi-photon observables. These could be exploited for both fundamental understanding of quantum-optical processes as well as applications by harnessing these unsuspected resources. This article is part of the theme issue 'Celebrating the 15th anniversary of the Royal Society Newton International Fellowship'.

Anisotropic qubit-photon interactions inducing multiple antibunching-to-bunching transitions of photons

We investigate photon correlations in the open anisotropic quantum Rabi model via quantum dressed master equation. Multiple antibunching-to-bunching transitions are generally exhibited at deep-strong qubit-photon coupling, which becomes vanishing in the standard open quantum Rabi model. The observed two-photon statistics can be well described analytically within a few lowest eigenstates at low temperatures. It is revealed that the additional photon antibunching effect mainly originates from the selection rule of the correlation-measurement-induced eigenstate transitions. Furthermore, we also unravel the phenomena that higher-order correlation function lifts up dramatically once passing the crossing point of excited states, which is attributed to the on-off switch of dominant cooperative transition with level crossing. We hope these results may fertilize the analysis of the nonclassical photon statistics in anisotropic coupled qubit-photon systems.

Hiding Images in Quantum Correlations.

Photon-pair correlations in spontaneous parametric down-conversion are ubiquitous in quantum photonics. The ability to engineer their properties for optimizing a specific task is essential, but often challenging in practice. We demonstrate the shaping of spatial correlations between entangled photons in the form of arbitrary amplitude and phase objects. By doing this, we encode image information within the pair correlations, making it undetectable by conventional intensity measurements. It enables the transmission of complex, high-dimensional information using quantum correlations of photons, which can be useful for developing quantum communication and imaging protocols.

Analytic evolution for complex coupled tight-binding models: Applications to quantum light manipulation

We present analytic solutions to the evolution in generalized tight-binding models, which consider complex first-neighbor couplings with equal amplitude and arbitrary phases. Our findings provide a powerful tool to efficiently calculate expectation values and correlations within the system, which are otherwise difficult to compute numerically. We apply our results to relevant examples in quantum light manipulation using -port linear couplers, describing the evolution of single (multi)-mode squeezing, single-photon added (subtracted) Gaussian states, and second-order site-to-site photon correlations. Significantly, our analytic results outperform standard numerical calculations. Our study paves the way for a comprehensive mathematical framework describing the spatial evolution of quantum states across a wide range of physical systems governed by the tight-binding model. Published by the American Physical Society 2024

Dynamics of metal formation upon radiation-chemical reduction of Cd2+ ions in aqueous solutions: Morphology of cadmium precipitate

The dynamics of metal formation upon radiation-chemical reduction of Cd2+ ions in aqueous solutions in the presence of НCOONa and morphology of cadmium precipitate were studied. The dynamics process and the morphology were characterized by dynamic light scattering, photon correlation spectroscopy, scanning electron microscopy, and turbidimetry. The formation of aqueous dispersions of the metal with the initial particle size of approximately 0.20 ± 0.05 μm was demonstrated. The metal particles undergo agglomeration with time; as a result, their size increases to 2–3 μm. The process completes with the formation of the precipitate. A feature of the sediment morphology is the developed structure of its surface and high porosity. The pores (from 0.5 μm to several microns) make up 80–90% of its volume. The aggregation is accelerated with an increase in the absorbed dose (amount of reduced metal) and in the concentration of salts in the solution.

Monitoring the dynamics of nanozeolite formation by combined in situ coherent small angle X-ray scattering techniques

Understanding the dynamics of zeolite formation is key to synthesising high-quality zeolitic materials with controllable properties, in order to develop more efficient and performant materials. X-ray photon correlation spectroscopy (XPCS) using coherent X-rays offers new possibilities for in situ observation of nano to micron-scale fluctuation dynamics during crystal growth. An in situ cell, which is capable of collecting time-resolved coherent X-ray scattering data under hydrothermal conditions has been developed and used to study, by in situ XPCS combined with small and wide angle X-ray scattering, zeolite formation and dynamics. Analysis of the results using two-time correlations enables to accurately identify the successive growth and crystallisation steps, revealing the dissolution process of the LTA topology during the SOD growth. This approach opens a powerful new avenue for studying the dynamics of nanomaterials formation, phase transitions and growth processes under in situ conditions that will enable profound insights into the nanoscale synthesis mechanisms.

Biexciton Emission in CsPbBr3 Nanocrystals: Polar Facet Matters.

The metal halide perovskite nanocrystals exhibit a remarkable tolerance to midgap defect states, resulting in high photoluminescence quantum yields. However, the potential of these nanocrystals for applications in display devices is hindered by the suppression of biexcitonic emission due to various Auger recombination processes. By adopting single-particle photoluminescence spectroscopy, herein, we establish that the biexcitonic quantum efficiency increases with the increase in the number of facets on cesium lead bromide perovskite nanocrystals, progressing from cube to rhombic dodecahedron to rhombicuboctahedron nanostructures. The observed enhancement is attributed mainly to an increase in their surface polarity as the number of facets increases, which reduces the Coulomb interaction of charge carriers, thereby suppressing Auger recombination. Moreover, Auger recombination rate constants obtained from the time-gated photon correlation studies exhibited a discernible decrease as the number of facets increased. These findings underscore the significance of facet engineering in fine-tuning biexciton emission in metal halide perovskite nanocrystals.