Solar energy is pollution‐free with less impact on the ecosystem, but it has limitations due to its intermittent nature attributed to sun availability for specific hours, resulting in less energy ...conservation efficiency. Similar to the purpose of carvings on the leaves to collect water, we are presenting a nanometer‐thick layer of silicon or chalcogenide with fused silica for photons enhancement in red and the blue portion of the spectrum within the solar energy reaching the earth's surface. The design is based on nanorod imprints on micrometer‐sized conventional fused silica, ensuring better absorption and transportation toward hybrid photovoltaic cells. Hybrid solar cells (comprising silicon and perovskites) are typically termed the future of solar power, but will not be discussed here. Effective area, optical power concentration, and second‐ and higher‐order dispersions can further help design and develop the photon concentrators.
A novel design for a plasmonic sensor, consisting of a metal–insulator–metal waveguide with a coupled circle-semi-ring resonator is proposed and investigated in this paper. We carried out the ...theoretical analysis for the wave-guiding characteristics by utilizing the two-dimensional (2D) finite-difference time-domain method. The effects of the electromagnetic wave transmission, field profile distribution, temperature and refractive index (RI) sensing characteristics on the structural parameters were studied in detail. The simulation results indicate that proposed sensor possesses a RI sensitivity up to 990 nm/refractive index unit and a temperature sensitivity of − 0.42 nm/°C with optimized geometric parameters. The compact waveguide structure may be widely utilized in areas of sensing and integrated circuits.
Multiple cladding modes can exist in a small-core optical fiber unaccompanied by core modes, yet this fact has not been sufficiently explored in the literature to date. In this paper, we study the ...self-imaging of cladding modes in small-core optical fiber interferometers. Our analytical and numerical simulations and experiments show that unlike the self-imaging of core modes, self-imaging of cladding modes only appears at a set of discrete positions along the interferometer axis with an equal spacing corresponding to some discrete values of fiber core radius. This is the first observation of the discrete self-imaging effect in multimode waveguides. More strikingly, the self-imaging period of cladding modes grows exponentially with fiber core radius, unlike the quadratic relationship in the case of core modes. The findings bring new insights into the mode propagation in an optical fiber with a core at micro/nanoscale, which may open new avenues for exploring multimode fiber technologies in both linear and nonlinear optics.
In this paper, a novel polarization-independent hybrid plasmonic coupler based on a T-shaped slot waveguide is proposed and investigated by numerical simulations using the finite element method. The ...structure supports both the TE-polarized slot waveguide mode and the TM-polarized plasmonic mode, offering a greater possibility to achieve the polarization-independent operation. The simulation results show that with proper structural parameters, the waveguide coupler with high extinction ratios of 31.2 dB (TE) and 30 dB (TM) and low insertion losses of 0.38 dB (TE) and 2.04 dB (TM) can be achieved at a telecommunication wavelength of 1550 nm. An investigation of the influence of structural perturbations indicates that the proposed coupler also has a good tolerance to fabrication errors. The proposed structure has potential applications in the field of subwavelength integrated photonic circuits.
The well-known tradeoff between the propagation loss and mode confinement is a critical consideration for the plasmonic waveguide structures. Aiming to overcome this limitation, in this paper, we ...propose a compact plasmonic waveguide consisting of two identical dielectric wedge waveguides symmetrically placed on each side of a nanowedge-patterned thin metal film. The systematical analysis has demonstrated that the light can be confined to approximate 3000th of the diffraction spot size (ranging from λ 2 /10 604 to λ 2 /972) without sacrificing the propagation length (ranging from 1680 to 4724 μm). Compared to the recent published structure which achieved the best tradeoff, to the best of our knowledge, the proposed waveguide could achieve a 9-fold enhanced mode confinement for the same propagation length and a 2.4-fold outspread propagation length for the same mode confinement.
Mode‐locking is an increased focus area due to the augmented requirement of ultra‐short and high‐intensity optical pulses for varied applications. Tunable mode‐locked lasers capable of operating in ...the infrared range at high repetition frequency brought innovative opportunities for insensitive and accurate laser surgery. As one important application of optical pulse propagation in an optical fiber, we have discussed a dual‐ring hybrid mode‐locked fiber laser using modulator, and saturable absorber. The active mechanism, saturable absorber, and the nonlinear optical loop mirror result in an output with a peak power of 16 dBm, and 80 fs full‐width at half‐maximum with a high duty cycle. It occupies a small space and is easy to achieve miniaturization and intensification; the laser output can be adjusted by varying multiple parameters such as pump, input, doped fiber length, modulator (including modulation signal), saturable absorber, and other devices.
In this paper, a review of numerical methods for design and analysis of nano/micro-sized optical waveguides is carried out. Besides discussing various types of optical waveguides, design of few ...structures is also presented using FDTD, BPM, and FEM algorithms. Subsequently, few optical devices based upon integration of more than one optical waveguide have also been revealed. Modal effective index analysis and its impact on waveguide designing/signal propagation has also been brought into consideration. Optical waveguides characterization has been carried out by computing second-order and higher order dispersion characteristics, which is vital for information interchange and other nonlinear phenomena. It is anticipated that this effort will help readers in understanding the requirement (subsequently selection) of tools for the design and analysis of optical waveguides.
Seeking better surface plasmon polariton (SPP) waveguides is of critical importance to construct the frequency-agile terahertz (THz) front-end circuits. We propose and investigate here a new class of ...semiconductor-based slot plasmonic waveguides for subwavelength THz transport. Optimizations of the key geometrical parameters demonstrate its better guiding properties for simultaneous realization of long propagation lengths (up to several millimeters) and ultra-tight mode confinement (~λ
/530) in the THz spectral range. The feasibility of the waveguide for compact THz components is also studied to lay the foundations for its practical implementations. Importantly, the waveguide is compatible with the current complementary metal-oxide-semiconductor (CMOS) fabrication technique. We believe the proposed waveguide configuration could offer a potential for developing a CMOS plasmonic platform and can be designed into various components for future integrated THz circuits (ITCs).
In this letter, an ultra-compact plasmonic polarization beam splitter (PBS) is proposed and investigated by numerical simulations using the finite element method. The PBS is based on a three-core ...plasmonic directional coupler, which uses a long range surface plasmon polaritons waveguide as the middle waveguide to achieve polarization selective coupling. The calculations show that with proper structural parameters, the PBS with low insertion losses of 0.17 and 0.25 dB for TE and TM polarizations, respectively, and high extinction ratios of 20.17 and 19.83 dB for TE and TM polarizations, respectively, can be realized at a telecommunication wavelength of 1550 nm. Furthermore, an insertion loss and an extinction ratio > 14 dB can be realized across the entire C-band for both TE and TM polarizations.
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