Activity

A deep investigation into the interaction between light and matter, beginning with the fundamental laws of classical electromagnetism, represented by Maxwell’s equations, and extending to the quantum optical realm, persists as a captivating field of research. In this research, a novel silver volcano-like fiber-optic probe (sensor 1), for surface-enhanced Raman scattering (SERS) is presented, as far as we are aware. Employing the nascent quasi-normal mode (QNM) method, we rigorously calculate the Purcell factor for lossy open-system responses, which are characterized by complex frequencies. Through this calculation, the modification in the radiation rate is determined when the particle moves from the excited state ‘e’ to the ground state ‘g’. faah signal Lastly, we implement a quantum mechanical model of the Raman process, including the Lindblad master equation, to predict the plasmonic structure’s SERS spectrum. For quantitative prediction of sensor 1’s SERS performance, we utilize sensor 2, a routinely employed SERS probe, modified with a structured array of silver nanoparticles, and a quantum mechanical model. A remarkable correspondence exists between the predictions and the experimental outcomes. In conjunction with other analyses, the FDTD (finite-difference time-domain) solver was used to estimate the all-fiber Raman response of both sensors, resulting in a reasonable spread of SERS performance values in comparison with experimental findings. The findings of this research imply potential applications in real-time, remote detection of biological species and in vivo diagnostics. The integrated FDTD and quantum optics models enable the analysis of emitter behavior in the vicinity of arbitrarily shaped plasmonic structures.

Photonic molecules, capable of realizing complex optical energy modes that simulate states of matter, find utility in quantum, linear, and nonlinear optical systems. To fully exploit photonic molecules’ capabilities, a rise in the intricacy of their energy states is indispensable, along with flexible, controllable, consistent, high-resolution energy state engineering and low-power tuning capabilities. A controllable photonic molecule, integrated within a silicon nitride platform, is demonstrated, characterized by three strongly coupled ring resonators with high quality factors, individually tuned using ultralow-power thin-film lead zirconate titanate (PZT). Six tunable supermodes emerge from this process, offering complete control over their degeneracy, location, and splitting degree. Despite resonance shifts, the PZT actuator design ensures narrow PM energy state linewidths below 58 MHz. The resonance splitting-to-width ratio improves by over an order of magnitude to 58, while power consumption per actuator remains at 90 nW, with a 1-dB photonic molecule loss. The PZT-controlled resonator, strongly coupled, provides excellent resolution and controllability in the accessing of supermodes. Due to the silicon nitride platform’s minimal signal loss from visible to infrared wavelengths and its unique three-individual-bus, six-port design, the outcomes suggest a multitude of innovative device designs with applications ranging from tunable lasers and high-order suppression ultranarrow-linewidth lasers to dispersion engineering, optical parametric oscillators, physics simulations, and advancements in atomic and quantum photonics.

Remote sensing of vectorial vibration is reported, achieved through locally stabilized Mach-Zehnder interferometers (MZIs) with the aid of commercial multi-core fiber (MCF). Vibration acquisition of a remote vectorial kind is accomplished through hexa-MZIs with a shared common reference arm, which are built using a 7-core MCF. Locally placed optical phase-locked loops (OPLLs), precisely coupled, not only counteract environmental uncertainties but also ensure constant and calibrated operation amongst the various Mach-Zehnder interferometers (MZIs), thereby guaranteeing stable remote sensing. This further guarantees a linearized phase detection, which subsequently enhances the sensing sensitivity and dynamic range. This all-fiber design, capitalizing on the symmetrical geometric distribution within the 7-core MCF’s cores, enables highly accurate and vectorial extraction of remote vibrations using a simplified remote architecture. We achieve vectorial remote sensing of vibrations, with a precision of 0.076 meters for the angle and 0.3603 meters for the displacement, respectively, across a 10-kilometer range.

Is the increased autofocusing speed, facilitated by a linear chirp factor, correlated with a shorter or longer focal length, leaving researchers perplexed? This letter focuses on a circular Airyprime beam to unravel this enigma. Focal length adjustment’s impact on enhancing abrupt autofocus is contingent upon the exponential decay factor ‘a’ and the dimensionless primary ring radius. When ‘a’ assumes a sufficiently small magnitude, a critical dimensionless radius value is discernible. Should the dimensionless radius exceed its critical value, the focal length will diminish, thereby bolstering the abrupt autofocusing capability. A dimensionless radius less than the critical value results in an extended focal length, bolstering the abrupt autofocusing ability. The critical value of the dimensionless radius diminishes as a value increases, until it approaches zero. The physical mechanisms enabling quick autofocusing through changes in focal length are investigated.

Entangled qudits, the high-dimensional entangled states, are instrumental in the field of quantum information. Preparing entangled qudits in a manner that is both efficient and easy to operate remains a significant challenge in the field of quantum technology. Employing spontaneous parametric downconversion, we illustrate a method for engineering frequency entanglement in qudits. A classical-quantum mapping is forged between the spatial (pump) and spectral (biphotons) degrees of freedom through the proposal’s use of an angle-dependent phase-matching condition within a nonlinear crystal. The pump profile’s spatial structure is categorized into multiple bins, which subsequently defines the down-converted biphotons’ arrangement into discrete frequency modes within the combined spectral domain. Our approach delivers a workable and productive method for the creation of a high-dimensional frequency entangled state. A three-dimensional entangled state was generated via a homemade variable slit mask, serving as an experimental demonstration.

The desire for polarization control through an external source is prominent in applied optics and photonics, as it significantly expands the possible configurations of an optical system. We report a novel electrically controlled polarization beam splitter (PBS) using nematic liquid crystal (LC) confined between two equilateral prisms. The presented LC-PBS allows for operation in two operational modes, the non-splitting mode and the polarization-splitting mode. The device’s responsiveness and flexibility is due to the external voltage’s ability to switch the PBS’s mode, thereby activating it. Bistable operation with stable modes, a wide splitting angle, a broad operating range, and economical fabrication methods are key attributes of the proposed electrically controlled PBS.

Numerical investigation of platicon stability in hot cavities, considering normal group velocity dispersion, was performed at the intersection of Kerr and thermal nonlinearities. In the stability analysis, numerous combinations of pump amplitude, thermal nonlinearity coefficient, and thermal relaxation time were examined. The study found that a positive thermal effect, where nonlinear and thermal resonance shifts exhibit the same direction, correlates with the stability of wide, high-energy platicons. In contrast, narrow platicons find stability through a negative thermal coefficient.

Topological phase Dirac-Weyl semimetal showcases the unique coexistence of both Dirac and Weyl points in momentum space. This research proposes a photonic Dirac-Weyl semimetal by integrating screw rotation symmetries into a spatially inversion-asymmetrical system. Experimental analysis of a metacrystal structure, realistic in its portrayal, is anticipated. The Z2 topology of Dirac points, discernible through the (010) surface states, is directly dependent on the screw rotation symmetries’ presence. In parallel, two exceptional pairs of Weyl points, synchronised at the same frequency, enjoy the protective properties of the D2d point group symmetry. A frequency interval, free from impurities, hosts the Dirac points and Weyl points. The proposed photonic Dirac-Weyl semimetal constitutes a versatile stage for investigating the interaction between Dirac and Weyl semimetals and subsequently enabling the fabrication of novel photonic topological devices.

For the purpose of optical tweezer design, this letter describes a simple structure comprising a high-index substrate covered by a thin metallic layer. A pulling or attractive optical force component manifests itself through the interaction of the field scattered by the particle with the incident plane wave, influenced by the proposed structure. The elliptical polarization of the induced dipole moment on the particle is instrumental in the excitation of surface plasmons (SPs), which causes improvement in this component. To fully explore the proposed method’s diverse capabilities, we dissect two primary configurations: reflection, where the plane wave impinges on the particle from its position; and transmission, where the wave strikes from the substrate. Using the reflection scheme with finite-thickness metal layers, our results demonstrate pulling forces that significantly surpass those generated by a single metallic interface, exceeding them by more than a factor of two. We demonstrate that the transmission approach outperforms the reflection scheme in maximizing pulling forces. Improving the pulling force via interactions between nano-particles and surface plasmon fields, our contribution is valuable in realizing simple plasmonic schemes.