arXiv subjects

Marcelo I. Davanco

Publications and source records attributed to Marcelo I. Davanco.

4 recordsLinked to original sources

arXiv2025

Broadband photonic structures to achieve high coupling efficiencies and Purcell factors with dark and interlayer excitons in 2D materials

Horizontal slot waveguides are planar photonic structures with a guided mode which is strongly polarized in the out-of-plane direction and tightly confined in a sub-wavelength region of lower refractive index. We show through FDTD simulations that this mode can lead to coupling efficiencies $β>80\%$ and Purcell factors $F_P>10$ for some types of dark intralayer excitons in transition metal dichalcogenide (TMD) monolayers -- more aplty named ``gray excitons'', as their out-of-plane dipole does couple to adequately polarized light -- as well as interlayer excitons in TMD heterostructures. These figures indicate a path to the strong coupling regime for gray and interlayer excitons, while bright excitons are poorly coupled to the slot mode and experience Purcell suppression for $λ>\SI{1}{\micro\meter}$. A significant hurdle towards strong coupling, however, is the low oscillator strengths of these two excitonic species. We use the Tavis-Cummings model to show that a horizontal-slot racetrack resonator can overcome this difficulty and reach a cooperativity $C>>1$, albeit sacrificing the broadband characteristic of waveguides.

quant-ph↗

arXiv2023

Traceable localization enables accurate integration of quantum emitters and photonic structures with high yield

Traceability to the International System of Units (SI) is fundamental to measurement accuracy and reliability. In this study, we demonstrate subnanometer traceability of localization microscopy, establishing a metrological foundation for the maturation and application of super-resolution methods. To do so, we create a master standard by measuring the positions of submicrometer apertures in an array by traceable atomic-force microscopy. We perform correlative measurements of this master standard by optical microscopy, calibrating scale factor and correcting aberration effects. We introduce the concept of a localization uncertainty field due to optical localization errors and scale factor uncertainty, with regions of position traceability to within a 68 % coverage interval of +/- 1 nm. These results enable localization metrology with high throughput, which we apply to measure working standards that we fabricate by electron-beam lithography, validating the accuracy of mean pitch and closing the loop for disseminating and integrating reference arrays. We then apply our novel methods to calibrate an optical microscope with a sample cryostat, accounting for thermal contraction by use of a submicrometer pillar array in silicon as a reference material and elucidating complex distortion. This new calibration enables the accurate integration of quantum emitters and photonic structures with high yield, as we demonstrate theoretically through simulations of the dependence of the Purcell factor of radiative enhancement on registration errors across a wide field. Our study illuminates the challenges and opportunities of achieving traceable localization for comparison of position data across lithography and microscopy systems, from ambient to cryogenic temperatures.

physics.optics↗

arXiv2016

Acousto-optic and opto-acoustic modulation in piezo-optomechanical circuits

Acoustic wave devices provide a promising chip-scale platform for efficiently coupling radio frequency (RF) and optical fields. Here, we use an integrated piezo-optomechanical circuit platform that exploits both the piezoelectric and photoelastic coupling mechanisms to link 2.4 GHz RF waves to 194 THz (1550 nm) optical waves, through coupling to propagating and localized 2.4 GHz acoustic waves. We demonstrate acousto-optic modulation, resonant in both the optical and mechanical domains, in which waveforms encoded on the RF carrier are mapped to the optical field. We also show opto-acoustic modulation, in which the application of optical pulses gates the transmission of propagating acoustic waves. The time-domain characteristics of this system under both pulsed RF and pulsed optical excitation are considered in the context of the different physical pathways involved in driving the acoustic waves, and modeled through the coupled mode equations of cavity optomechanics.

physics.optics↗

arXiv2015

Slot-Mode Optomechanical Crystals: A Versatile Platform for Multimode Optomechanics

We demonstrate slot-mode optomechanical crystals, a class of device in which photonic and phononic crystal nanobeam resonators separated by a narrow slot are coupled through optomechanical interactions. In these geometries, nanobeam pairs are patterned so that a mechanical breathing mode is confined at the center of one beam, and a high quality factor (Qo>10^5) optical mode is confined in the slot between the beams. Here, we produce slot-mode devices in a stoichiometric Si3N4 platform, with optical modes in the 980 nm band, coupled to breathing mechanical modes at 3.4 GHz, 1.8 GHz, and 400 MHz. We exploit the high Si3N4 tensile stress to achieve slot widths down to 24 nm, which leads to enhanced optomechanical coupling, sufficient for the observation of optomechanical self-oscillations at all studied frequencies. We utilize the slot mode concept to develop multimode optomechanical systems with triple-beam geometries, in which two optical modes are coupled to a single mechanical mode, and two mechanical modes are coupled to a single optical mode. This concept allows great flexibility in the design of multimode chip-scale optomechanical systems with large optomechanical coupling at a wide range of mechanical frequencies.

physics.optics↗