Optical control over multi-membrane materials

Project Information

OCOMM

Grant agreement ID: 101105894

DOI

10.3030/101105894

Project closed

EC signature date 13 March 2023

Start date 1 April 2023

End date 31 May 2025

Funded under

• Marie Skłodowska-Curie Actions (MSCA)

Total cost

No data

EU contribution

€ 222 727,68

Coordinated by

CHALMERS TEKNISKA HOGSKOLA AB
Sweden

Periodic Reporting for period 1 - OCOMM (Optical control over multi-membrane materials)

Reporting period: 2023-04-01 to 2025-05-31

Summary of the context and overall objectives of the project

Optomechanical devices use the interaction of light with mechanical elements through radiation pressure. They both explore fundamental questions of quantum mechanics of macroscopic system and facilitate technical applications like wavelength conversion and quantum-limited sensing. To date most of these systems only use single or few mechanical and optical resonator sites.

Having control over several mechanical resonators, how they link and interact with optical modes, would open a perspective to realize optically programmable, integrated acoustic circuits.

A potential platform for this are Megahertz-range mechanical resonators, where the optomechanical spring effect can be used to substantially shift the mechanical resonance frequency. The required number of photons in the optical mode can be reached within miniaturized optical resonators based on reflective optical fiber tips creating so-called fiber Fabry-Perot cavities (FFPCs).

The goal of OCOMM is to develop such a micromechanical platform for coupled mechanical resonators with controllable properties that is interfaced using FFPCs for a stepping towards an optically interfaced controllable mechanical systems that is comprised of many mechanical elements.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

Within OCOMM both an ambient condition and a high-vacuum-based fiber Fabry-Perot optical cavity setup have been constructed allowing to interface optical and optomechanical reflective structures on chip at Chalmers. This can be done with variable cavity lengths or with a feedback-stabilized length to the probing laser source. Using this type of setup membrane-based photonic crystal structures have and continue to be investigated.

Different micromechanical platforms have been experimentally investigated for their potential for multi-mode mechanical materials. Reaching beyond the original goals of the project, a novel material platform that would even allow a combination with a potentially scalable, piezoelectric tuning interface have been demonstrated. This and similar, strained thin-film, mechanical resonator platforms are currently pushed towards mechanical realization of mechanical materials within optical microcavities.

In collaboration with international partners, multi-mode mechanical resonator structures inside an optical microcavity with collective optomechanical coupling have been implemented. These are based on direct laser-written structures that have shown to exhibit substantial optomechanical spring shifts. Their collective mechanical properties are currently still under investigation.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Within the project, contributions to a novel Aluminum Nitride-based mechanical resonator structure in the MHz regime with high quality factor have been made. Aside the demonstrated complex mechanical resonator structures, these may exploit the in-built piezoelectricity for electrical tunable mechanics, or allow the demonstration of highly sensitive and functionalized sensing tools of force or acceleration.

The combination of micro-optical Fabry-Perot cavities with photonic crystal structures has deepened our understanding of this experimental platform. Inherent limitations were analyzed with respect to its optical performance, and on the underlying physics of the optomechanical coupling in this system benefiting further research by laying out requirements and design paradigms for this technological approach.

Collaborative work on direct laser-written multi-membrane mechanical resonators have led to measurements of mechanically coupled systems interfaced using FFPCs. The novel fabrication approach allows for an upscaling of this technology to multimode structures comprising many membranes inside a single optical resonator that can be used to control the system. Collective coupling to the optical mode were observed and can be facilitated in the future to increase optomechanical coupling rates and steer mechanical excitation in the system.

Fiber Fabry-Perot cavity above a photonic crystal membrane chip.