Nanobenders: efficient piezoelectric actuators for widely tunable nanophotonics at CMOS-level voltages

TL;DR

This paper introduces nanobenders, compact piezoelectric actuators capable of efficiently tuning nanophotonic components at CMOS-level voltages, achieving large displacements and optical resonance shifts with minimal voltage and area.

Contribution

The authors propose and demonstrate nanobenders, a novel piezoelectric actuator design that provides significantly larger displacement per volt than standard materials, enabling efficient, low-voltage tuning of nanophotonic devices.

Findings

Achieved ~5 nm/V optical resonance tuning

Demonstrated ~400 linewidth tuning range with 4 V

Generated tens of nanometers displacement per volt

Abstract

Tuning and reconfiguring nanophotonic components is needed to realize systems incorporating many components. The electrostatic force can deform a structure and tune its optical response. Despite the success of electrostatic actuators, they suffer from trade-offs between tuning voltage, tuning range, and on-chip area. Piezoelectric actuation could resolve all these challenges. Standard materials possess piezoelectric coefficients on the order of ${0.01}~\text{nm/V}$, suggesting extremely small on-chip actuation using potentials on the order of one volt. Here we propose and demonstrate compact piezoelectric actuators, called nanobenders, that transduce tens of nanometers per volt. By leveraging the non-uniform electric field from submicron electrodes, we generate bending of a piezoelectric nanobeam. Combined with a sliced photonic crystal cavity to sense displacement, we show tuning of an optical resonance by $\sim 5~\text{nm/V}~({0.6}~\text{THz/V})$ and between $1520$ and $1560~\text{nm}$ ($\sim 400$ linewidths) with only $ {4}~\text{V}$. Finally, we consider other tunable nanophotonic components enabled by nanobenders.