Theoretical investigation of piezo-optic effect in photonic crystal nanocavity for nanostrain detection

This paper reports a theoretical investigation of the strain sensitive effect of a 2D photonic crystal (PhC) nanocavity resonator for mechanical sensing applications. The nanocavity is created by missing a circle of air holes in the array of triangular lattice of air holes. The strain sensitivity of a high quality factor PhC nanocavity has been investigated based on the finite element method (FEM) using ANSYS™ software and the finite different time domain (FDTD) simulation using CrystalWave™. Linear relationship between strain and shift of the resonant wavelength of the cavity has been obtained. The strain-induced resonant wavelength shifts or strain sensitivities to longitudinal and transverse strains have been theoretically determined to be 1.9 nm/mε and 0.25 nm/mε, respectively. The fabrication process of the test sample is carried out.