Integrated optical force sensors using focusing photonic crystal arrays

Integrated optical force sensors using focusing photonic crystal arrays

Guo, J. (TU Delft QN/Groeblacher Lab)
Norte, R.A. (TU Delft QN/Groeblacher Lab)
Groeblacher, S. (TU Delft QN/Groeblacher Lab)

2017

Mechanical oscillators are at the heart of many sensor applications. Recently several groups have developed oscillators that are probed optically, fabricated from high-stress silicon nitride films. They exhibit outstanding force sensitivities of a few aN/Hz1/2 and can also be made highly reflective, for efficient detection. The optical read-out usually requires complex experimental setups, including positioning stages and bulky cavities, making them impractical for real applications. In this paper we propose a novel way of building fully integrated all-optical force sensors based on low-loss silicon nitride mechanical resonators with a photonic crystal reflector. We can circumvent previous limitations in stability and complexity by simulating a suspended focusing photonic crystal, purely made of silicon nitride. Our design allows for an all integrated sensor, built out of a single block that integrates a full Fabry-Pérot cavity, without the need for assembly or alignment. The presented simulations will allow for a radical simplification of sensors based on high-Q silicon nitride membranes. Our results comprise, to the best of our knowledge, the first simulations of a focusing mirror made from a mechanically suspended flat membrane with subwavelength thickness. Cavity lengths between a few hundred µm and mm should be directly realizable.

http://resolver.tudelft.nl/uuid:f8215f99-7133-4ef2-b70e-56b1b92fc94d

https://doi.org/10.1364/OE.25.009196

1094-4087

Optics Express, 25 (8), 9196-9203

Institutional Repository

journal article

© 2017 J. Guo, R.A. Norte, S. Groeblacher