Photon Research Articles

Enhancing Two-Photon Absorption of Green Fluorescent Protein by Quantum Entanglement.

Exploring the electronic states of molecules through excitation with entangled and classical photon pairs offers new insights into the nature of light-matter interactions and stimulates the development of quantum spectroscopy. Here, we address the importance of temporal entanglement of light in two-photon absorption (TPA) upon the S0 → S1 transition by the green fluorescent protein (GFP)─a key molecular unit in the bioimaging of living cells. By invoking a two-level model applicable when permanent dipole pathways dominate the two-photon transition, we derive a convenient closed-form analytical expression for the entangled TPA strength. For the first time, we disclose specific molecular properties that cause classical and entangled two-photon absorptions to be qualitatively different when exciting the same state. We reveal a new nonclassical contribution to the TPA strength, which is defined by the magnitude and directional alignment of permanent dipole moments in the initial and final states. Using high-level electronic structure theory, we show that the nonclassical contribution is intrinsically larger than the classical counterpart in GFP, leading to an enhancement of the TPA strength due to quantum entanglement by several orders of magnitude. We also present evidence that the classical and quantum TPA strengths can be modulated differently by the protein environment and demonstrate how to control the outcome by alterations in the local electric field of the protein caused by a single amino acid replacement. Our findings establish physical grounds for enhancing TPA in photoactive proteins by quantum entanglement, facilitating the rational design of high-efficiency biomarkers for future applications that utilize quantum light.

Quantum Frequency Combs with Path Identity for Quantum Remote Sensing

Quantum sensing promises to revolutionize sensing applications by employing quantum states of light or matter as sensing probes. Photons are the clear choice as quantum probes for remote sensing because they can travel to and interact with a distant target. Existing schemes are mainly based on the quantum illumination framework, which requires quantum memory to store a single photon of an initially entangled pair until its twin reflects off a target and returns for final correlation measurements. Existing demonstrations are limited to tabletop experiments, and expanding the sensing range faces various roadblocks, including long-time quantum storage and photon loss and noise when transmitting quantum signals over long distances. We propose a novel quantum sensing framework that addresses these challenges using quantum frequency combs with path identity for remote sensing of signatures (“qCOMBPASS”). The combination of one key quantum phenomenon and two quantum resources—namely, quantum-induced coherence by path identity, quantum frequency combs, and two-mode squeezed light—allows for quantum remote sensing without requiring quantum memory. The proposed scheme is akin to a quantum radar based on entangled frequency-comb pairs that uses path identity to detect, range, or sense a remote target of interest by measuring pulses of one comb in the pair that never traveled to the target but that contains target information “teleported” by quantum-induced coherence by path identity from the other comb in the pair that traveled to the target but is not detected. We develop the basic qCOMBPASS theory, analyze the properties of the qCOMBPASS transceiver, and introduce the qCOMBPASS equation—a quantum analog of the well-known LIDAR equation in classical remote sensing. We also describe an experimental scheme to demonstrate the concept using two-mode squeezed quantum combs. qCOMBPASS can strongly impact various applications in remote quantum sensing, imaging, metrology, and communications. These applications include detection and ranging of low-reflectivity objects, measurement of small displacements of a remote target with precision beyond the standard quantum limit (SQL), standoff hyperspectral quantum imaging, discreet surveillance from space with low detection probability (detect without being detected), very-long-baseline interferometry, quantum Doppler sensing, quantum clock synchronization, and networks of distributed quantum sensors. Published by the American Physical Society 2024

Photonic Simulation of Majorana-Based Jones Polynomials

By braiding non-Abelian anyons it is possible to realize fault-tolerant quantum algorithms through the computation of Jones polynomials. So far, this has been an experimentally formidable task. In this Letter, a photonic quantum system employing two-photon correlations and nondissipative imaginary-time evolution is utilized to simulate two inequivalent braiding operations of Majorana zero modes. The resulting amplitudes are shown to be mathematically equivalent to Jones polynomials. The high fidelity of our optical platform allows us to distinguish between a wide range of links, such as Hopf links, Solomon links, Trefoil knots, Figure Eight knots and Borromean rings, through determining their corresponding Jones polynomials. Our photonic quantum simulator represents a significant step towards executing fault-tolerant quantum algorithms based on topological quantum encoding and manipulation. Published by the American Physical Society 2024

Quantum Hall and Light Responses in a 2D Topological Semimetal

Quantum Hall and Light Responses in a 2D Topological Semimetal

Shielding properties of the kombucha-derived bacterial cellulose

AbstractLiving organisms are constantly exposed to cosmic, terrestrial, and internal sources of radiation. As a result, they have developed natural radioprotective mechanisms. However, in some cases, these mechanisms may not be sufficient. Elevated doses and prolonged exposure to radiation, such as during radiotherapy or in extreme environments like spaceflight, can cause damage to DNA and increase the abundance of reactive oxygen species, which can affect biological processes. In contrast to synthetic ingredients, naturally produced radioprotective materials have good biocompatibility and are easy to recycle. This work investigates the radioprotective properties of the hydrogel biofilm produced by the kombucha microbial consortium. The shielding properties of kombucha’s bacterial cellulose (KBC) were examined using gamma quanta with energies ranging from 122 to 1408 keV and an AmBe neutron source. The native form of KBC contains more than 80% water content. To enhance the radioprotection of kombucha’s biofilm, metallic components (K, Fe, Mxenes) and biological additives were tested. Rhodobacter sphaeroides and Synechocystis sp. PCC6803, which are resistant to oxidative stress, were added to the cultivation media. Physical properties were characterized using microscopy, ion leaching, and contact angle measurements. Post-processed dried KBC wristbands were analyzed for absorption parameters to enhance protective shielding. Possible levels of radioprotection for various types of bacterial cellulose thickness and forms were computed based on the obtained results. The findings encourage the use of bacterial cellulose in a circular economy for future bioregenerative systems.

Polarization entanglement enabled by orthogonally stacked van der Waals NbOCl2 crystals

Polarization entanglement holds significant importance for photonic quantum technologies. Recently emerging subwavelength nonlinear quantum light sources, e.g., GaP and LiNbO3 thin films, benefiting from the relaxed phase-matching constraints and volume confinement, have shown intriguing properties, such as high-dimensional hyperentanglement and robust entanglement anti-degradation. Van der Waals (vdW) NbOCl2 crystal, with strong optical nonlinearities, has emerged as a potential candidate for ultrathin quantum light sources. However, polarization entanglement is inaccessible in the NbOCl2 crystal due to its unfavorable nonlinear susceptibility tensor. Here, by leveraging the twist-stacking degree of freedom inherently in vdW systems, we showcase the preparation of polarization entanglement and quantum Bell states.

Strong photoluminescence enhancement from a WS2 atomic layer integrated on a metallic nanogroove array with intermediate plasmon–exciton coupling

The coupling between surface plasmons and excitons in transition metal dichalcogenides (TMDs) plays crucial roles in light emission, nonlinear optics, and quantum information processing. However, the intermediate plasmon–exciton coupling has not been reported in the TMD-integrated metallic nanoarray. Herein, we demonstrate the intermediate coupling behavior between surface plasmons in the silver nanogroove array and excitons in 2D layered tungsten disulfide (WS2). The results show that the reflection spectra of the silver nanogroove array possess an obvious reflection dip at the wavelength of ∼630 nm due to the generation of surface plasmons. The experiment results are well consistent with the numerical simulations. When the silver nanoarray is integrated with a trilayer WS2, there exists a distinct coupling between surface plasmons and A excitons in WS2. The temporal coupled-mode theory analysis shows that the plasmon–exciton coupling locates in the intermediate plasmon–exciton coupling region. The intermediate coupling can give rise to the strong photoluminescence (PL) enhancement of 48-fold in WS2. The wavelength of the PL peak presents a red shift with the increase of the temperature. This work paves a new pathway for the generation of plasmon–exciton coupling and the PL enhancement in atomic-layer TMDs.

Exploring supersymmetry: Interchangeability between Jaynes-Cummings and anti-Jaynes-Cummings models

The supersymmetric connection that exists between the Jaynes-Cummings (JC) and anti-Jaynes Cummings (AJC) models in quantum optics is unraveled entirely. A new method is proposed to obtain the temporal evolution of observables in the AJC model using supersymmetric techniques, providing an overview of its dynamics and extending the calculation to full photon counting statistics. The approach is general and can be applied to determine the high-order cumulants given an initial state. The analysis reveals that engineering the collapse-revival behavior and the quantum properties of the interacting field is possible by controlling the initial state of the atomic subsystem and the corresponding atomic frequency in the AJC model. The substantial potential for applications of supersymmetric techniques in the context of photonic quantum technologies is thus demonstrated. Published by the American Physical Society 2024

Room-temperature waveguide integrated quantum register in a semiconductor photonic platform

Quantum photonic integrated circuits are reshaping quantum networks and sensing by providing compact, efficient platforms for practical quantum applications. Despite continuous breakthroughs, integrating entangled registers into photonic devices on a CMOS-compatible platform presents significant challenges. Herein, we present single electron-nuclear spin entanglement and its integration into a silicon-carbide-on-insulator (SiCOI) waveguide. We demonstrate the successful generation of single divacancy electron spins and near-unity spin initialization of single 13C nuclear spins. Both single nuclear and electron spin can be coherently controlled and a maximally entangled state with a fidelity of 0.89 has been prepared under ambient conditions. Based on the nanoscale positioning techniques, the entangled quantum register has been further integrated into SiC photonic waveguides for the first time. We find that the intrinsic optical and spin characteristics of the register are well preserved and the fidelity of the entangled state remains as high as 0.88. Our findings highlight the promising prospects of the SiCOI platform as a compelling candidate for future scalable quantum photonic applications.

Cosmic rays from annihilation of heavy dark matter particles

The origin of the ultra high energy cosmic rays via annihilation of heavy stable, fermions “f”, of the cosmological dark matter (DM) is studied. The particles in question are supposed to be created by the scalaron decays in R2 modified gravity. The novel part of our approach is the assumption that the mass of these carriers of DM is slightly below than a half of the scalaron mass. In such a case the phase space volume becomes tiny. It leads to sufficiently low probability of “f” production, so their average cosmological energy density could be equal to the observed energy density of dark matter. Several regions of the universe, where the annihilation could take place, are studied. They include the whole universe under the assumption of homogeneous energy density, the high density DM clump in the galactic center, the cloud of DM in the Galaxy with realistic density distribution, and high density clumps of DM in the Galaxy. Possible resonance annihilation of ff¯ into energetic light particles is considered. We have shown that the proposed scenario can successfully explain the origin of the ultrahigh energy flux of cosmic rays where canonical astrophysical mechanisms are not operative.

Detection efficiency characterization for free-space single-photon detectors: Measurement facility and wavelength-dependence investigation

In this paper, we present an experimental apparatus for the measurement of the detection efficiency of free-space single-photon detectors based on the substitution method. We extend the analysis to account for the wavelength dependence introduced by the transmissivity of the optical window in front of the detector's active area. Our method involves measuring the detector's response at different wavelengths and comparing it to a calibrated reference detector. This allows us to accurately quantify the efficiency variations due to the optical window's transmissivity. The results provide a comprehensive understanding of the wavelength-dependent efficiency, which is crucial for optimizing the performance of single-photon detectors in various applications, including quantum communication and photonics research. This characterization technique offers a significant advancement in the precision and reliability of single-photon detection efficiency measurements.

Retraction Note: Quantum photonics based health monitoring system using music data analysis by machine learning models

Retraction Note: Quantum photonics based health monitoring system using music data analysis by machine learning models

Reconfiguration of Quantum Photonic Integrated Circuits Using Auxiliary Fields

Reconfiguration of Quantum Photonic Integrated Circuits Using Auxiliary Fields

Dual-Band Polarization Control with Pairwise Positioning of Polarization Singularities in Metasurfaces.

Emerging applications of metasurfaces in classical and quantum optics are driving the need for precise polarization control of nearly-degenerate, high quality (Q)-factor modes. However, current approaches to creating specifically polarized pairs of modes force a trade-off between maintaining high Q factors and robustness. Here, we solve this challenge by employing pairwise generation, annihilation, and positioning of polarization singularities, derived from symmetry-guaranteed pairs of symmetry-protected bound states in the continuum. We experimentally demonstrate this design paradigm in silicon metasurfaces with mode splittings of ≈20 nm, mode splitting deviations as low as 1nm, and Q factors up to 200. This approach opens new avenues for enhancing metasurface performance across a diverse range of applications, including sensing, modulating, nonlinear mixing, and generating quantum light.

Van der Waals NbOCl2 Nanodisks for Enhanced Second-Harmonic Generation.

Niobium oxide dichloride (NbOCl2), a van der Waals crystal, exhibits exceptional second-harmonic generation (SHG) with high conversion efficiency, making it a promising candidate for on-chip quantum light sources, photon modulators, and sensors. To increase its suitability for integrated photonic systems, it is crucial to explore strategies for further improving optical nonlinear conversion efficiency. In this article, dielectric metasurfaces are employed to enhance SHG from patterned NbOCl2 nanodisks. By precisely tuning their geometric parameters to achieve optical resonance near the excitation wavelength, a remarkable 25-fold enhancement in second-harmonic emission at 400 nm is achieved in nanodisks compared to the unpatterned thin film. The strong field enhancement within the NbOCl2 nanodisks at nanophotonic resonances contributes to the observed increase in SHG. This work offers an effective strategy for boosting SHG in van der Waals NbOCl2 thin films, paving the way for the development of efficient nonlinear optical components in integrated nanophotonics.

Quantum Pair Generation in Nonlinear Metasurfaces with Mixed and Pure Photon Polarizations.

Metasurfaces are highly effective at manipulating classical light in the linear regime; however, effectively controlling the polarization of nonclassical light generated from nonlinear resonant metasurfaces remains a challenge. Here, we present a solution by achieving polarization engineering of frequency-nondegenerate biphotons emitted via spontaneous parametric down-conversion in GaAs metasurfaces, utilizing quasi-bound states in the continuum (qBIC) resonances to enhance biphoton generation. Through comprehensive polarization tomography, we demonstrate that the emitted photons' polarization directly reflects the qBIC mode's far-field properties. Furthermore, we show that both the type of qBIC mode and the symmetry of the meta-atoms can be tailored to control each single-photon polarization state, and that the subsequent two-photon polarization states are nearly separable, offering potential applications in the heralded generation of single photons with adjustable polarization. This work provides a significant step toward utilizing metasurfaces to generate quantum light and engineer their polarization, a critical aspect for future quantum technologies.

Retraction Note: Quantum Photonics advancements enhancing health and sports performance

Retraction Note: Quantum Photonics advancements enhancing health and sports performance

Investigating the fractional Caudrey-Dodd-Gibbon-Sawada-Kotera equation: an iterative framework for nonlinear wave dynamics

Abstract This paper addresses the solution of the fractional Caudrey-Dodd-Gibbon-Sawada-Kotera (CDGSK) equation using the Conformable Laplace Decomposition Method (CLDM). The CDGSK equation, a fundamental model in wave dynamics and fluid mechanics, is explored for its applications in quantum mechanics and nonlinear optics. By employing fractional calculus, we demonstrate how fractional derivatives influence the physical characteristics of wave propagation in both optical and quantum systems. The exact solutions obtained provide insight into soliton behavior, essential for understanding wave-particle interactions in quantum fields and light–matter interactions in optics. The fractional nature of the equation allows for more accurate modeling of non-integer order dynamics commonly found in optical fibers and quantum waveguides. The CLDM method proves to be highly effective, providing approximate solutions with minimal computational effort. These findings offer significant contributions to the fields of quantum mechanics and nonlinear optics, where the fractional CDGSK equation can be applied to solve complex wave equations with great accuracy.

Overview of the Factors Influencing the Efficiency of PV Solar Cells

PV technology works through the direct conversion of sunlight into electricity, a process based on the photoelectric effect. This phenomenon happens when specific materials absorb light particles, leading to the release of electrons. Capturing these electrons produces an electric current. Which can be harnessed as usable electricity. The development of more efficient PV system designs and enhancements in their operation and maintenance are key areas of current innovation. These advances are crucial for improving the overall performance and sustainability of solar energy systems, making them a more viable and dependable option for future energy needs. In the literature there are plenty of papers on solar energy, in order to advance the research on this subject we needs up to date information on the current situation. As such is lacking at present, A current literature review of this phenomenon is reffered for more detail.

Hybrid Source of Quantum Light for Generation of Frequency Tunable Fock States.

We propose a scheme for quantum-light generation in a nonlinear cavity hybridized with a two-level system and theoretically show that, when excited by a series of controlled pump pulses, the hybrid source generates Fock states with high probabilities, e.g., one- and two-photon states can be generated near on demand, and Fock states with up to seven photons with a probability above 50%. The tailorable nature of the nonlinear cavity allows for generating Fock states with arbitrary frequencies, even with a fixed two-level system, creating fundamentally new opportunities in all areas of quantum technologies.