Applied Physics B最新文献

We introduce an advanced methodology for determining the topological charge of a vortex Bessel beam via light-atom interactions in a closed-loop three-level atomic system. This technique exploits the interplay between an optical Bessel beam with topological charge (ell _p) and a microwave Bessel beam with topological charge (ell _{mu }), which collectively induce a spatially varying, phase-sensitive atomic susceptibility. This interaction manifests in a distinct pattern of alternating absorption and transparency regions in the transverse plane, governed by the medium’s resultant topological charge, (ell = ell _{mu } - ell _{p}). The transparency windows selectively allow specific beam portions to propagate, while absorption windows block others, transforming the beam’s concentric rings into structured patterns of alternating bright and dark strips. The number of these strips directly correlates with the Bessel beam’s topological charge. Analytical expressions for atomic susceptibility elucidate the mechanism underlying this transformation, enabling simultaneous and precise measurement of the topological charges of both beams. The superior sensitivity of this approach opens up transformative possibilities for applications in communications, microscopy, and optical metrology. Furthermore, varying the relative phase between the optical and microwave beams induces a controlled angular rotation of the structured beam, offering enhanced maneuverability over beam orientation. This robust approach not only facilitates precise characterization of structured light but also supports advanced applications in optical computing, information processing, and sensing technologies.

Characteristics of photon plasmon coupling in black phosphorus (BP) embedded between chiroferrite layer is analyzed in THz frequency spectrum. The frequency behavior and propagation characteristics of SPPs are analyzed under various physical parameters i.e., chirality parameter ((xi)), gyrotropy (({mu}_{2})), carrier density (({n}_{s})), and the number of layers ((N)). Numerical results indicate the significant dependency of surface plasmon frequency on these parameters along (({sigma}_{ac})) and (({sigma}_{zz})) conductivities of BP. As chirality parameter ((xi)) increases, the plasmonic frequency increases for both conductivities. While gyrotropy (({mu}_{2})) shifts the plasmonic response, with larger values of ({mu}_{2}) leading to decrease the plasmonic frequency. The carrier density ({n}_{s}) also influences the plasmon frequency, with higher ({n}_{s}) values resulting in higher frequencies for both (({sigma}_{ac})) and (({sigma}_{zz})). Furthermore, the number of BP layers (N) has notable impact, as an increase in N causes a steeper rise in frequency for both (({sigma}_{ac})) and (({sigma}_{zz})). Propagation loss or imaginary part of propagation constant for different carries density is also analyzed for both conductivities. Based on numerical results ({sigma}_{ac}) is suitable for higher frequencies compared to ({sigma}_{zz})​. This suggests that ({sigma}_{ac})​ might possess properties that facilitate its performance or responsiveness at higher frequencies in contrast to ({sigma}_{zz})​. However, ({sigma}_{zz}) exhibits higher effective mode index for the proposed waveguide structure. Additionally, modulating carrier density can control both the phase velocity and propagation length. The proposed waveguide structure holds promising potential for plasmonic community to fabricate nanophotonic devices due to anisotropy of chiroferrite and BP medium in THz frequency regime.

Efficient peptide adsorption on metasurfaces is essential for advanced biosensing applications. In this study, we demonstrate how ellipsometric measurements coupled with numerical simulations allow for real-time tracking of temporin-SHa peptide adsorption on gold metasurfaces. By characterizing spectral shifts at 660 nm, 920 nm, and 1000 nm, we reveal a rapid saturation of surface coverage after 3.5 h, with a significant preferential adsorption at the resonator ends. Our approach provides a novel methodology for monitoring peptide binding, which could be applied to a wide range of biosensor designs.

A direct optimal calculation method was proposed to determine the thickness, refractive index, and extinction coefficient of thin films solely from experimental transmittance data. Unlike conventional approaches, this method does not rely on any dispersion model. Numerical and experimental analyses confirm its accuracy. The variations in refractive index and extinction coefficient curves demonstrate the chemical bond properties of chalcogenide films. This work provides a useful method for analyzing the optical parameters of the optical films.

The process of transmitting an arbitrary unknown quantum state through quantum and classical channels between distant sender and receiver locations is commonly referred to as quantum teleportation. When physical presence at the quantum teleportation destination is impossible, we utilize quantum remote estimation to analyze the received information. This study introduces a novel geometrical approach to quantum teleportation based on a dipolar interacting magnetic system. Furthermore, we examine quantum remote estimation of the initial phase at the output of the geometric quantum teleportation via the current model. The research explores the impact of quantum-level crossings resulting from the magnetic anisotropies of dipolar interacting systems on the processes of quantum teleportation and quantum remote estimation. The results indicate that quantum teleportation and quantum remote estimation encounter challenges at the boundary of quantum level crossings but can be optimized in other states, such as the ground states. Our finding highlights the need for further investigations into geometric quantum teleportation and its implications.

Trapped-ion technology is a leading approach for scalable quantum computing. A key element of ion trapping is reliable loading of atomic sources into the trap. While thermal atomic ovens have traditionally been used for this purpose, laser ablation has emerged as a viable alternative in recent years, offering the advantages of faster and more localized loading with lower heat dissipation. Calcium is a well-established ion for qubit applications. Here we examine a range of calcium sources for ablation and provide a comprehensive analysis of each. We consider factors such as ease of use, temperature and yield of the ablation plume, and the lifetime of ablation spots. For each target, we estimate the number of trappable atoms per ablation pulse for a typical surface and 3D ion trap.

Quantum optical integrated circuits are revolutionizing quantum information processing by utilizing integrated photonics technology to create complex optical circuits on a single chip. Historically, these circuits encountered various challenges in quantum applications, but recent advancements have enabled them to meet the rigorous demands of both research and industry. A key area of exploration is the establishment and maintenance of quantum properties within photonic substrates. Bragg grating structures, essential for many optical applications, are anticipated to significantly contribute to the development of integrated circuits. However, they face a challenge with dispersion, which can threaten the integrity of quantum states. When entangled photons pass through a waveguide, their correlation function tends to broaden due to this dispersion. To address this issue, the study emphasizes the importance of apodizing the grating structure, as this can help reduce the broadening of the correlation function, provided that the apodization function’s standard deviation can adapt to variations in the refractive index. The proposal of apodized waveguide gratings aims to enhance the correlation of biphotons, offering a promising strategy for advancing the field.

A sub-nanosecond blue laser with a large longitudinal mode spacing at 486 nm was demonstrated based on a frequency-doubled potassium titanyl phosphate optical parametric oscillator. The pump laser was a 532 nm green laser with a pulse width of 0.76 ns at the maximum pulse energy of 4 mJ. With a cavity optical length of 8.9 mm, the output energy of 972 nm signal laser reached 0.8 mJ, corresponding to a conversion efficiency of 20%. The signal laser was frequency-doubled to a blue laser with a longitudinal mode spacing of 16.8 GHz, matching the frequency spacing of seawater Brillouin scattering signal peaks excited by 486 nm laser. The spectral linewidth, pulse width and single pulse energy of the blue laser were 0.28 nm, 0.57 ns, and 80 μJ, respectively. This blue laser provides a reliable laser source for verifying the feasibility of multi-longitudinal-mode laser technique in oceanic high-spectral-resolution lidar.

We theoretically investigate photo-excitation of electron–hole pairs and high harmonic generation in the bulk of zinc oxide (ZnO) subjected to intense femto-second laser pulses with mid-infrared wavelength. The main microscopic mechanism of solid-state HHG is identified by separating resonant from non-resonant non-linear optical responses in the photo-excited solid. We obtain an effective light-matter interaction in which electrons are subject to weak atto-second pulse train with the second harmonic of the drive laser frequency being the repetition frequency in the train. Under a condition of constructive interference of electronic transitions between consecutive half-cycles of the drive laser pulse, resonant-like excitation of electron–hole pairs occurs which contribute to the multi-cycle accumulation of photo-current. The inter-band motion of charge carriers creates rapidly oscillating electric dipole moment, which emits continuum bremsstrahlung-like radiation during each half-cycle of the drive laser pulse. If the laser-cycles of the drive pulse are identical, the emissions from consecutive half-cycles are phase-coherent, and their mutual interference produces a frequency comb in the spectral domain, which is composed of the odd-integer harmonics of the drive laser frequency. The spectral intensity of each harmonic scales with the fourth power of the total number of cycles in the drive pulse. In contrast, if consecutive cycles in the pulse are non-identical, the interference pattern in the frequency domain is less well defined and blurred. The importance of the pulse envelope for producing clean frequency combs as observed in the experiments is discussed. Good semi-quantitative agreement with the experimental data is found: clean and well defined odd-order harmonic peaks extending well beyond the band edge of ZnO are exhibited for laser linearly polarized at right angles to the optical axis of the crystal.