查看更多>>摘要：Post-compression of ultra-short laser pulses via self-phase modulation is routinely employed for the generation of laser pulses with optical bandwidths reaching far beyond the laser gain limitations. Although high compression factors can be routinely achieved, the compressed pulses typically suffer from temporal quality degradation. We numerically and experimentally analyze the deterioration of different measures of temporal quality with increasing compression factor and show how appropriate dispersion management and cascading of the post-compression process can be employed to limit the impact of this effect. The demonstrated saturation of pulse quality degradation at large compression factors puts novel femtosecond laser architectures based on post-compressed picosecond or even nanosecond laser systems in sight. Published by Optica Publishing Group under the terms of the Creative Commons Attribution 4.0 License.
查看更多>>摘要：Two-photon interference of broadband chaotic light in a Michelson interferometer is theoretically and numerically studied with a two-photon-absorption detector when polarizations are taken into account. Under the frame of quantum optics, the theoretical analysis is based on two-photon interference and Feynman path integral theory. A two-photon coherence matrix is introduced to calculate the second-order interference pattern. Our research shows that polarization is another dimension, as well as time and space, to tune the second-order interference pattern in the two-photon interference process. Polarizations can act as switches to manipulate the interference process and may open the door to some new experimental schemes. The quantum optical vector model is also helpful to understand the physics of second-order interference when the light source is quantum. (C) 2022 Optica Publishing Group
查看更多>>摘要：The coupling between plasmons in two-dimensional materials and photons can be enhanced by a Fabry-Perot (FP) cavity, leading to the formation of cavity plasmon polaritons (CPPs). In this work, we theoretically investigate the effects of substrate on CPPs in monolayer (ML) molybdenum disulfide (MoS2) embedded in an asymmetric FP cavity. The optical conductivity of ML MoS2 used here is described by the Drude-Smith model, in which the substrate-induced electronic loralization effect is considered. This effect has been experimentally demonstrated for chemical vapor deposition grown MoS2 in our recent work. Herein, the investigation shows the existence of three types of CPPs in this asymmetric plasmonic system. Meanwhile, we also demonstrate that the substrate can affect the properties of these modes through different mechanisms. These results not only can give us insight into the effects of substrate on plasmon polaritons but also remind us that the differences between the realistic optical parameters of MoS2 and the ideal ones cannot be neglected in many situations. Moreover, we hope this study can push forward the design and optimization of plasmonic devices based on MoS2, such as sensors, attenuators, and detectors. (C) 2022 Optica Publishing Group
查看更多>>摘要：This paper presents a plasmonic pressure sensor via an optical metal-insulator-metal (MIM) waveguide structure. The proposed pressure sensor is composed of a ring resonator, a stub, and a U-shaped resonator coupled to the bus waveguide. The finite-difference time-domain method (FDTD) is used to study the Fano resonance (FR) characteristics and magnetic field distributions. Results show that the Fano line shapes can be independently tuned by the geometrical parameters. When pressure is exerted on the U-shaped resonator layer, the deformation leads to the shift of the resonant wavelength. The calculated maximum pressure sensitivities are 10.96 and 10.5 nm/MPa for FR 2, and FR 3, respectively (MPa = 10(6) Pa). The good linear relationship between the pressure and resonance wavelength indicates that the proposed nano-scale structure can find potential applications in the fields of nano-biosensing and biomedical sensing. (C) 2022 Optica Publishing Group
Westerkam, Anders M.Sonne, Jesper L. W.Danielsen, Karl G.Skovsen, Esben...
7页
查看更多>>摘要：Transmittance spectra of an all-dielectric sub-wavelength grating exhibiting Fano resonances are studied both experimentally and theoretically for a frequency interval spanning several terahertz using both s- and p-polarized radiation. Modeled spectra based on the rigorous coupled wave analysis are shown to be in good agreement with the Fourier transform of measured time-domain transmission spectra for normal and angled incidence. Finally, a model is presented that explains Fano resonance frequencies by matching the propagation constant of a discrete set of guided modes to wavenumbers that both match diffraction orders in the grating and are in a range that allows propagation in the dielectric medium. (C) 2022 Optica Publishing Group
查看更多>>摘要：We propose a modified generalized Harvey-Shack model by adding the empirical correction factor related to the scattering angle on the basis of the original theory. The result shows that the modified model reduces the root mean square error (RMSE) from less than 2% to less than 1%, and the relative peak error from less than 50% to less than 20%, which significantly improves the accuracy of scattering prediction. The prediction of the Rayleigh-Rice model is not as good as the Harvey-Shack model. The RMSE of the Rayleigh-Rice model is within 2.5%, and the relative peak error is within 60%. (C) 2022 Optica Publishing Group
Upadhyaya, Anup M.Sharan, PreetaSrivastava, Maneesh C.
7页
查看更多>>摘要：The strain sensing action of a photonic integrated microcantilever induced by the binding of biomolecules such as antibodies and antigens is an important factor in biosensing applications. Since sensitivity is the key factor in sensor performance for early detection of any bio analyte, increasing the sensitivity of the photonic integrated microcantilever becomes more critical. This can be achieved by varying the geometry of the microcantilever. Two photonic integrated microcantilever configurations-stepped profile and T-shaped microcantilevers-are considered for pressure sensing, and a comparative analysis between both designs is presented. The sensitivity of the microcantilever is improved for a small magnitude of force such as 0.1 MPa to 0.4 MPa for the T-shaped profile of the microcantilever. The resonant wavelength and wavelength shift between two structures are evaluated for various ranges of applied pressure. Sensitivities of the stepped profile and T-shaped microcantilevers are calculated as 0.58 nm/MPa in the range of 10 MPa to 25 MPa, and 92 nm/MPa in the range of 0.1 MPa to 0.4 MPa, respectively. Simulation results show that the proposed sensing configuration, i.e., T-shaped microcantilever, has high sensitivity and a significant range of wavelength at low-pressure values. This capability of the T-shaped microcantilever enhances feasibility for future fabrication and implementation in different biomedical applications. (C) 2022 Optica Publishing Group
查看更多>>摘要：We investigate the electromagnetic response of anisotropic (non-spherical) copper antimony disulfide (CuSbS2) nanoparticles and layers embedded with them using computational methods. To this end, we calculate the scattering and absorption efficiencies of oblate spheroidal CuSbS2 nanoparticles using the surface integral equation method. We find strong dependence of the response depending on the anisotropy of the spheroids and their orientation with respect to the electric field polarization of incoming radiation. Thin spheroids display a sharp plasmonic resonance in the ultraviolet, which is observed only for the electric field polarization along the short axis. Fano resonances that appear in the near infrared (NIR) blueshift when the short axis length is reduced, and they can be either strongly suppressed or enhanced depending on the relative orientation of the spheroid. We further investigate the optical response of thin layers containing CuSbS2 spheroids at a low volume fraction using a Monte Carlo method. We find that the response of these layers can be considerably modified by changing the short axis length and the orientation of particles within the layer with respect to polarization. Our results demonstrate the potential of anisotropic dielectric particles for polarization-dependent-response applications such as solar devices and NIR sensors. (C) 2022 Optica Publishing Group
查看更多>>摘要：One of the considerable disadvantages of a metasurface (MS) is frequency-dependent behavior, which largely restricts its practical applications. To overcome this challenge, a MS is designed to generate vortex beams at three distinct terahertz (THz) frequencies. Specifically, a unit-cell structure comprising three resonators is proposed to operate at three distinct THz frequencies. The cross-polarized reflection coefficients of the unit-cell structure are greater than 70% under circularly polarized (CP) incidence. Based on the geometric phase principle, the full 2 pi phase shift can be obtained at each frequency by rotating the corresponding orientation angles of the three resonators. By carefully arranging the unit-cell structure, orbital angular momenta (OAMs) with topological charges of l = +/- 1, -2, and, -3 at 0.706 THz, 1.143 THz, and 1.82 THz, respectively, can be generated for a normally incident right CP wave, and OAMs with topological charges of l = -3, -2, and -1 can be generated for a normally incident left CP wave. The generated reflective vortex beams through the designed MS have good mode purity up to 85% at 0.706 THz, 84% at 1.143 THz, and 74.7% at 1.82 THz, respectively. Moreover, the designed reflective MS reveals a convenient and low-cost way to generate vortex beams with different/same OAM modes at three different resonance frequencies and is beneficial for potential applications in THz communication. (C) 2022 Optica Publishing Group
查看更多>>摘要：This erratum reports corrections to the temporal axes in Figs. 12 and 13 of J. Opt. Soc. Am. B 39, 662 (2022). (C) 2022 Optica Publishing Group
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