Efficient coupling between dielectric waveguide modes and exterior plasmon whispering gallery modes

AbstractThe spectral and energy characteristics of the tunable thin planar dielectric resonator with the movable metal mirror are researched. It is found that the high-Q HE-polarized whispering gallery modes (WGMs) are effectively excited in such a resonator by the dielectric waveguide. A mode set of the tunable thin planar dielectric resonator depends on the presence of an air gap in its design. Changing the height of the air gap affects the energy characteristics of the tunable thin planar dielectric resonators (DR). Shifting the resonant fields of WGMs from the dielectric disk to the air gap is the reason for this effect. It is shown that at certain heights of the air gap, increasing the unloaded Q-factor of the tunable thin planar DR and improving the excitation efficiency of WGMs in it is achieved.

Download Full-text

Out-of-plane trion emission in monolayer WSe2 revealed by whispering gallery modes of dielectric microresonators

Communications Materials ◽

10.1038/s43246-021-00157-8 ◽

2021 ◽

Vol 2 (1) ◽

Author(s):

Daniel Andres-Penares ◽

Mojtaba Karimi Habil ◽

Alejandro Molina-Sánchez ◽

Carlos J. Zapata-Rodríguez ◽

Juan P. Martínez-Pastor ◽

...

Keyword(s):

Room Temperature ◽

Close Contact ◽

Spectroscopic Method ◽

Whispering Gallery Modes ◽

Quantum Communications ◽

Whispering Gallery ◽

Plane Component ◽

Out Of Plane ◽

Efficient Coupling ◽

On Chip

AbstractThe manipulation of light emitted by two-dimensional semiconductors grounds forthcoming technologies in the field of on-chip communications. However, these technologies require from the so elusive out-of-plane photon sources to achieve an efficient coupling of radiated light into planar devices. Here we propose a versatile spectroscopic method that enables the identification of the out-of-plane component of dipoles. The method is based on the selective coupling of light emitted by in-plane and out-of-plane dipoles to the whispering gallery modes of spherical dielectric microresonators, in close contact to them. We have applied this method to demonstrate the existence of dipoles with an out-of-plane orientation in monolayer WSe2 at room temperature. Micro-photoluminescent measurements, numerical simulations based on finite element methods, and ab-initio calculations have identified trions as the source responsible for this out-of-plane emission, opening new routes for realizing on-chip integrated systems with applications in information processing and quantum communications.

Download Full-text

Efficient coupling of free propagating light into Whispering Gallery Modes

EPJ Web of Conferences ◽

10.1051/epjconf/202125504002 ◽

2021 ◽

Vol 255 ◽

pp. 04002

Author(s):

Xavier Zambrana-Puyalto ◽

Davide D’Ambrosio ◽

Gianluca Gagliardi

Keyword(s):

Coupling Efficiency ◽

Whispering Gallery Mode ◽

Cylindrical Symmetry ◽

Whispering Gallery Modes ◽

Spherical Particles ◽

Whispering Gallery ◽

Efficient Coupling ◽

Mode Purity ◽

Experimental Values ◽

Dielectric Structures

Whispering Gallery Mode resonators are dielectric structures with cylindrical symmetry. They are typically excited with an evanescent field leaking out of a tapered fiber or a waveguide. It is also known that they can be excited with free propagating beams. In this work, we use a recently developed analytical model which quantitatively describes the coupling of free propagating beams into Whispering Gallery Modes for spherical particles. Using this model, we have been able to theoretically quantify the mode purity and the coupling efficiency of a resonant Whispering Gallery Mode of an order j*= 1456. We have observed that the transverse position of the beam plays a crucial role in determining the mode purity and coupling efficiency. Last but not least, we have verified that the coupling efficiency as well as the Q-factor predicted by our model are in an outstanding agreement with the experimental values measured on a microresonator of the same dimensions as the simulated one.

Download Full-text