Full Spatial Characterization of Entangled Structured Photons.

Vector modes are fully polarized modes of light with spatially varying polarization distributions, and they have found widespread use in numerous applications such as microscopy, metrology, optical trapping, nanophotonics, and communications. The entanglement of such modes has attracted significant interest, and it has been shown to have tremendous potential in expanding existing applications and enabling new ones. However, due to the complex spatially varying polarization structure of entangled vector modes (EVMs), a complete entanglement characterization of these modes remains challenging and time consuming. Here, we have used a time-tagging event camera to demonstrate the ability to completely characterize the entanglement of EVMs. Leveraging the camera's capacity to provide independent measurements for each pixel, we simultaneously characterize the entanglement of approximately 2.6×10^{6} modes between a bipartite EVM through measuring only 16 observables in polarization. We reveal that EVMs can naturally generate various polarization-entangled Bell states. This achievement is an important milestone in high-dimensional entanglement characterization of structured light, and it could significantly impact the implementation of related quantum technologies. The potential applications of this technique are extensive, and it could pave the way for advancements in quantum communication, quantum imaging, and other areas where structured entangled photons play a crucial role.

Integrating bioprocess and metagenomics studies to enhance humic acid production from rice straw.

Rice straw burning annually (millions of tons) leads to greenhouse gas emissions, and an alternative solution is producing humic acid with high added-value. This study aimed to examine the influence of a microbial consortium and other additives (chicken manure, urea, olive mill waste, zeolite, and biochar) on the composting process of rice straw and the subsequent production of humic acid. Results showed that among the fungal species, Thermoascus aurantiacus exhibited the most prominent impact in expediting maturation and improving compost quality, and Bacillus subtilis was the most abundant bacterial species based on metagenomics analysis. The highest temperature, C/N ratio reduction, and amount of humic acid production (Respectively in lab 61 °C, 54.67%, 298 g kg-1 and in pilot level 65 °C, 72.11%, 310 g kg-1) were related to treatments containing these microorganisms and other additives except urea. Consequently, T. aurantiacus and B. subtilis can be employed on an industrial scale as compost additives to further elevate quality. Functional analysis showed that the bacterial enzymes in the treatments had the highest metabolic activities, including carbohydrate and amino acid metabolism compared to the control. The maximum enzymatic activities were in the thermophilic phase in treatments which were significantly higher than that in the control. The research emphasizes the importance of identifying and incorporating enzymatically active strains that are suitable for temperature conditions, alongside the native strains in decomposing materials. This strategy significantly improves the composting process and yields high-quality humic acid during the thermophilic phase.

Manipulating the symmetry of transverse momentum entangled biphoton states.

Bell states are a fundamental resource in photonic quantum information processing. These states have been generated successfully in many photonic degrees of freedom. Their manipulation, however, in the momentum space remains challenging. Here, we present a scheme for engineering the symmetry of two-photon states entangled in the transverse momentum degree of freedom through the use of a spatially variable phase object. We demonstrate how a Hong-Ou-Mandel interferometer must be constructed to verify the symmetry in momentum entanglement via photon "bunching/anti-bunching" observation. We also show how this approach allows generating states that acquire an arbitrary phase under the exchange operation.

High-speed imaging of spatiotemporal correlations in Hong-Ou-Mandel interference.

The Hong-Ou-Mandel interference effect lies at the heart of many emerging quantum technologies whose performance can be significantly enhanced with increasing numbers of entangled modes one could measure and thus utilize. Photon pairs generated through the process of spontaneous parametric down conversion are known to be entangled in a vast number of modes in the various degrees of freedom (DOF) the photons possess such as time, energy, and momentum, etc. Due to limitations in detection technology and techniques, often only one such DOFs can be effectively measured at a time, resulting in much lost potential. Here, we experimentally demonstrate, with the aid of a time tagging camera, high speed measurement and characterization of two-photon interference. With a data acquisition time of only a few seconds, we observe a bi-photon interference and coalescence visibility of ∼64% with potentially up to ∼2 × 103 spatial modes. These results open up a route for practical applications of using the high dimensionality of spatiotemporal DOF in two-photon interference, and in particular, for quantum sensing and communication.

Impact of the COVID-19 pandemic on the stage and the type of surgical treatment of laryngeal cancer.

PURPOSE: Changes in the entire health care system during COVID-19 epidemic have affected the management of patients with head and neck cancer and posed several clinical challenges for ENT surgeons. Therefore, the present study aimed to investigate the effect of COVID-19 on the stage and the type of surgical treatments used in laryngeal cancer (including total laryngectomy, supracricoid partial laryngectomy (SCPL) and transoral laser microsurgery (TLM)) and also to compare the results of April 2020 to April 2021 with the previous year. MATERIALS AND METHODS: This cross-sectional study was performed on all patients with a diagnosis of laryngeal cancer who underwent surgery in the tertiary care center from April 2020 to April 2021 and the year before the pandemic in the same time. Demographic, cancer stage, and treatment data of all patients were recorded and analysis in two groups. RESULTS: Patients referred at the time of the virus outbreak; 111 were male and 5 were female, and in the group of patients referred before COVID-19, 90 were male and 12 were female. The type of surgical treatment of laryngeal cancer, mean time elapsed from sampling to surgery, stage of disease and mean tumor volume was statistically significant differences in patients before and during the outbreak. CONCLUSION: Patients who referred for diagnosis and treatment at the time of COVID-19 outbreak had more advanced stages of the disease and also the tumor volume was higher in them than patients who had referred before the outbreak. It is necessary to provide new solutions, education and treatment management for patients with laryngeal cancer in such pandemics.

Occult nodal metastasis in head and neck carcinoma patients treated with chemoradiotherapy.

BACKGROUND AND AIM: Neck lymph node metastasis plays an important role in the prognosis of patients with squamous cell carcinoma of the head and neck. The aim of this study was to evaluate the occult nodal metastasis in patients with head and neck squamous cell carcinoma (HNSCC) treated with chemo radiotherapy. METHODS: In this 5-year prospective study, patients with recurrent head and neck squamous cell carcinomas (HN-SCC) after primary treatment with chemoradiotherapy or radiotherapy that candidate for surgery were enrolled. In total, 50 patients with squamous cell carcinomas of the head and neck with N0 neck were included in the study. Age, initial location of recurrent tumor, T staging in primary and recurrent tumors, neck condition (N0 or N+), and pathology report for neck metastasis, number of affected lymph nodes and duration of tumor recurrence were examined. RESULTS: Out of 50 patients with mean age of 57.04 ± 14.4 years, 13 were female (26%) and 37 (74%) were male. In terms of primary tumor size, 52% (26 patients) were in T2 stage. The primary and recurrent tumor was located in the oral cavity in 33 patients (66%). Nine 0f 50 patients (18%) had occult metastases. CONCLUSION: It seems that END surgery is necessary for treatment the occult lymph node neck metastasis of recurrent head and neck cancers with N0 neck. Therefore, it is possible that END surgery has reduced cervical recurrence in these patients.

Two-photon interference: the Hong-Ou-Mandel effect.

Nearly 30 years ago, two-photon interference was observed, marking the beginning of a new quantum era. Indeed, two-photon interference has no classical analogue, giving it a distinct advantage for a range of applications. The peculiarities of quantum physics may now be used to our advantage to outperform classical computations, securely communicate information, simulate highly complex physical systems and increase the sensitivity of precise measurements. This separation from classical to quantum physics has motivated physicists to study two-particle interference for both fermionic and bosonic quantum objects. So far, two-particle interference has been observed with massive particles, among others, such as electrons and atoms, in addition to plasmons, demonstrating the extent of this effect to larger and more complex quantum systems. A wide array of novel applications to this quantum effect is to be expected in the future. This review will thus cover the progress and applications of two-photon (two-particle) interference over the last three decades.

Full-mode characterization of correlated photon pairs generated in spontaneous downconversion.

Spontaneous parametric downconversion is the primary source to generate entangled photon pairs in quantum photonics laboratories. Depending on the experimental design, the generated photon pairs can be correlated in the frequency spectrum, polarization, position-momentum, and spatial modes. Exploring the spatial modes' correlation has hitherto been limited to the polar coordinates' azimuthal angle, and a few attempts to study Walsh mode's radial states. Here, we study the full-mode correlation, on a Laguerre-Gauss basis, between photon pairs generated in a type-I crystal. Furthermore, we explore the effect of a structured pump beam possessing different spatial modes onto bi-photon spatial correlation. Finally, we use the capability to project over arbitrary spatial mode superpositions to perform the bi-photon state's full quantum tomography in a 16-dimensional subspace.

Experimental Demonstration of an Electrostatic Orbital Angular Momentum Sorter for Electron Beams.

The component of orbital angular momentum (OAM) in the propagation direction is one of the fundamental quantities of an electron wave function that describes its rotational symmetry and spatial chirality. Here, we demonstrate experimentally an electrostatic sorter that can be used to analyze the OAM states of electron beams in a transmission electron microscope. The device achieves postselection or sorting of OAM states after electron-material interactions, thereby allowing the study of new material properties such as the magnetic states of atoms. The required electron-optical configuration is achieved by using microelectromechanical systems technology and focused ion beam milling to control the electron phase electrostatically with a lateral resolution of 50 nm. An OAM resolution of 1.5ℏ is realized in tests on controlled electron vortex beams, with the perspective of reaching an optimal OAM resolution of 1ℏ in the near future.

Perichondritis due to a herpes zoster Infection after an Ear Piercing: a Case Report.

Nowadays piercing has become one of the most popular fashionable and cultural customs and people of all ages are interested in this cosmetic procedure. One of the common sites of piercing is ears which, like any other piercing, can bring about many complications like infection, inflammation, allergic reaction, keloid formation, and traumatic tearing. In this paper, we report a case of perichondritis due to Staphylococcal secondary infection to a primary herpes zoster infection following ear piercing.

Entanglement: quantum or classical?

From its seemingly non-intuitive and puzzling nature, most evident in numerous EPR-like gedanken experiments to its almost ubiquitous presence in quantum technologies, entanglement is at the heart of modern quantum physics. First introduced by Erwin Schrödinger nearly a century ago, entanglement has remained one of the most fascinating ideas that came out of quantum mechanics. Here, we attempt to explain what makes entanglement fundamentally different from any classical phenomenon. To this end, we start with a historical overview of entanglement and discuss several hidden variables models that were conceived to provide a classical explanation and demystify quantum entanglement. We discuss some inequalities and bounds that are violated by quantum states thereby falsifying the existence of some of the classical hidden variables theories. We also discuss some exciting manifestations of entanglement, such as N00N states and the non-separable single particle states. We conclude by discussing some contemporary results regarding quantum correlations and present a future outlook for the research of quantum entanglement.

Theoretical analysis on spatially structured beam induced mass transport in azo-polymer films.

The radiation force from paraxial beams possessing helical phase fronts causes twists on the surface of an azobenzene polymer sample, and leads to the formation of micro-scale structures. Here, we theoretically investigate the radiation force generated by spatially structured optical beams on a dispersive-absorptive substrate. We derive an analytical expression for the radiation force from spatially structured polarized beams, including, lemon, star, monstar and vector vortex beams in the paraxial regime. Finally, we extend our calculation for non-paraxial beams - optical beams under the tight-focusing regime - and simulate the transverse radiation forces numerically at the focal plane.

The role of core needle biopsy in parotid glands lesions with inconclusive fine needle aspiration.

OBJECTIVES: Usefulness of preoperative tissue sampling and pathology diagnoses in parotid gland tumors were accepted worldwide. We investigate the role of CNB in the parotid gland lesions when FNA results are inconclusive. METHODS: We conducted a cross sectional study to evaluate CNB results from fifty-two patients with history of parotid gland lesion and inconclusive previous fine needle aspiration. RESULTS: In this study, 45 out of 52 CNB results determined definite histological subtype diagnosis. Four CNB reports were inconclusive and three CNB results were compatible with malignancies, but did not define definite diagnosis. Calculated sensitivity for diagnosis of malignancy was 96% and specificity was 85%. Negative predictive value, positive predictive value, and accuracy for CNB in detecting malignancy, were calculated 94%, 90%, and 92%, respectively. CONCLUSIONS: When FNA is not conclusive, CNB may be used as a precise method to evaluate the parotid gland lesions.

Characterization of an underwater channel for quantum communications in the Ottawa River.

We examine the propagation of optical beams possessing different polarization states and spatial modes through the Ottawa River in Canada. A Shack-Hartmann wavefront sensor is used to record the distorted beam's wavefront. The turbulence in the underwater channel is analysed, and associated Zernike coefficients are obtained in real-time. Finally, we explore the feasibility of transmitting polarization states as well as spatial modes through the underwater channel for applications in quantum cryptography.

Interaction-free ghost-imaging of structured objects.

Quantum - or classically correlated - light can be employed in various ways to improve resolution and measurement sensitivity. In an "interaction-free" measurement, a single photon can be used to reveal the presence of an object placed within one arm of an interferometer without being absorbed by it. With a technique known as "ghost-imaging", entangled photon pairs are used for detecting an opaque object with significantly improved signal-to-noise ratio while preventing over-illumination. Here, we integrate these two methods to obtain a new imaging technique which we term "interaction-free ghost-imaging" (IFGI). With this new technique, we reduce photon illumination on the object by up to 26.5% while still maintaining at least the same image quality of conventional ghost-imaging. Alternatively, IFGI can improve image signal-to-noise ratio by 18% when given the same number of interacting photons as in standard ghost-imaging. IFGI is also sensitive to phase and polarisation changes of the photons introduced by a structured object. These advantages make IFGI superior for probing light-sensitive materials and biological tissues.

Compressed sensing of twisted photons.

The ability to completely characterize the state of a system is an essential element for the emerging quantum technologies. Here, we present a compressed-sensing-inspired method to ascertain any rank-deficient qudit state, which we experimentally encode in photonic orbital angular momentum. We efficiently reconstruct these qudit states from a few scans with an intensified CCD camera. Since it only requires a small number of intensity measurements, our technique provides an easy and accurate way to identify quantum sources, channels, and systems.

The use of CMVIg rescue therapy in cardiothoracic transplantation: A single-center experience over 6 years (2011-2017).

Cytomegalovirus (CMV) is the most important infectious agent in solid organ transplant recipients and has a major impact on morbidity and mortality. Most cases are well managed with antiviral agents, but CMV hyperimmune globulin (CMVIg) can be used alongside antiviral therapy for prophylaxis in high-risk thoracic organ recipients and to treat life-threatening CMV infection or disease. CMVIg may also improve antiviral host defences when genetic resistance to antivirals or unwanted side effects occur. In this single-center, retrospective study, we reviewed the CMVIg use to supplement antiviral therapy as a "rescue therapy" in cardiothoracic transplant recipients. These comprised 12 single lung, 11 double lung, and 12 heart transplant recipients. Patients received a median of 2 doses of CMVIg, most often in combination with ganciclovir or valganciclovir, and reduced immunosuppression. One week after rescue therapy was initiated, CMV DNA levels were significantly reduced, and after four weeks, CMV DNA was undetectable in 73% patients. Only one patient died as a result of CMV-related disease. No significant adverse effects were observed. We conclude that CMVIg rescue therapy is safe, well tolerated, and effective at controlling viral replication in cardiothoracic transplant recipients.

Quantum cryptography with twisted photons through an outdoor underwater channel.

Quantum communication has been successfully implemented in optical fibres and through free-space. Fibre systems, though capable of fast key and low error rates, are impractical in communicating with destinations without an established fibre link. Free-space quantum channels can overcome such limitations and reach long distances with the advent of satellite-to-ground links. However, turbulence, resulting from local fluctuations in refractive index, becomes a major challenge by adding errors and losses. Recently, an interest in investigating the possibility of underwater quantum channels has arisen. Here, we investigate the effect of turbulence on an underwater quantum channel using twisted photons in outdoor conditions. We study the effect of turbulence on transmitted error rates, and compare different quantum cryptographic protocols in an underwater quantum channel, showing the feasibility of high-dimensional encoding schemes. Our work may open the way for secure high-dimensional quantum communication between submersibles, and provides important input for potential submersibles-to-satellite quantum communication.