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Monolayer transition metal dichalcogenides (TMDCs), like MoS

The exciton–polaritonic states are generated by the strong interaction between photons and excitons in confined nanocavities. To achieve strong coupling between excitons in TMDCs and optical modes ...

Monolayer transition metal dichalcogenides (TMDCs), like MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$, feature direct bandgaps, strong spin-orbit coupling, and exciton-polariton interactions at the atomic scale, which could be harnessed for efficient light emission, valleytronics, and polaritonic lasing, respectively. Nevertheless, to build next-generation photonic devices that make use of these features, it is first essential to model the all-optical control mechanisms in TMDCs. Herein, a simple model is proposed to quantify the performance of a 35$\,$\textmu m long Si$_3$N$_4$ waveguide-integrated all-optical MoSe$_2$ modulator. Using this model, a switching energy of 14.6$\,$pJ is obtained for a transverse-magnetic (TM) and transverse-electric (TE) polarised pump signals at $\lambda =\,$480$\,$nm. Moreover, maximal extinction ratios of 20.6$\,$dB and 20.1$\,$dB are achieved for a TM and TE polarised probe signal at $\lambda =\,$500$\,$nm, respectively, with an ultra-low insertion loss of $, Comment: \copyright 2022 Optica Publishing Group. One print or electronic copy may be made for personal use only. Systematic reproduction and distribution, duplication of any material in this paper for a fee or for commercial purposes, or modifications of the content of this paper are prohibited

The ultrafast response and broadband absorption of all-optical graphene switches are highly desirable features for on-chip photonic switching. However, because graphene is an atomically thin material, its absorption of guided optical modes is relatively low, resulting in high saturation thresholds and switching energies for these devices. To boost the absorption of graphene, we present a practical design of an electrically-biased all-optical graphene switch that is integrated into silicon slot waveguides, which strongly confine the optical mode in the slotted region and enhance its interaction with graphene. Moreover, the design incorporates a silicon slab layer and a hafnia dielectric layer to electrically tune the saturation threshold and the switching energy of the device by applying DC voltages of, Accepted for publication in the Journal of Optics

In this paper, we analyze the performance of two tantalum-based boride (TaB and TaB2) microparticles as potential saturable absorbers for high-power fiber lasers. Both materials are ultrahigh temperature ceramics with melting points above 3000 °C, but with different crystalline structures: TaB has an orthorhombic structure (nearly isotropic), whereas TaB2 has a hexagonal structure (uniaxial, anisotropic). Despite their different crystalline structures, the microparticles have a similar low fluence attenuation (between 2.3 and 2.60 dB/μm) and modulation depths (around 2.0 dB/μm), but remarkable different saturation fluences: TaB has a saturation fluence of 160 μJ/cm2, whereas TaB2 has a saturation fluence of 110 μJ/cm2. The measured damage thresholds are 112 and 106 mJ/cm2/pulse for TaB and TaB2, respectively. When incorporated to a fiber laser, the materials produce pulses with durations of 345 ns, lower than those reported by our group in previous papers. The results show that the materials can find potential applications in high-power Q-switched lasers.

The strong light–matter interaction between the exciton of atomically thin transition metal dichalcogenides (TMDCs) and photonic nanocavities leads to the formation of unique hybrid light-matter quasiparticles known as exciton-polaritons. The newly formed mixed state has the advantages of the photonic part such as rapid propagation and low effective mass and the highly desirable optical properties of TMDC’s exciton, including the interparticle strong interactions nonlinearity and spin-valley polarization. These joint properties make such systems an ideal platform for studying many compelling physics phenomena and open the possibility of designing novel optoelectronic devices. This work reviews recent progress of strong coupling between exciton in TMDC and different resonant photonic structures, such as optical microcavities, plasmonic and all-dielectric nanocavities. Furthermore, we discussed the unique valleytronic and nonlinear properties of TMDC monolayers in the strong coupling regime. Finally, we highlighted some of the challenges and potential future research opportunities in this field.

We show that the addition of an array of silicon nitride nanowire resonator can boost the absorbance of a monolayer of WS2 from around 5-10% to 62% at the exciton wavelength of 620 nm.

Due to the large binding energy and direct bandgap, transition-metal dichalcogenides (TMDCs) monolayers have been considered a perfect platform for realising strong coupling at room temperature. It is well established that the quality factor (Q-factor) plays a crucial role in enhancing strong coupling. In this work, we demonstrate the improved strong coupling between the exciton of the WSe2 monolayer and the high Q cavity resonance based on symmetry protected magnetic dipole (MD) bound state in the continuum (BIC). We have found that the Rabi-splitting of the strongly coupled system could be largely enhanced by adjusting the location of the TMDC monolayer, increasing the Q-factor, and reducing the grating thickness. After carefully adjusting the three critical parameters, a Rabi-splitting as high as 38 meV was achieved limited by the oscillator strength of the WSe2 monolayer. Our system could be considered an excellent platform to realise ultra-thin polaritonic devices.

We present the results for two tantalum borides (TaB and TaB 2 ) as potential saturable absorbers for Q-switched lasers. When incorporated to a ring ytterbium laser operating at 1080 nm, they produced pulse widths as short as 345 ns.

A nanolaser using AlGaAs nanodisk is theoretically demonstrated based on anapole state. The radius and height of the nanodisk are optimized to be 240nm and 120nm through geometry tuning based on Mie scattering theory. We have achieved near-field lasing at 1017nm with linewidth around 3.5nm.