Proposal and numerical study of a flexible visible photonic crystal defect cavity for nanoscale strain sensors

A flexible photonic crystal cavity, consisting of a III V active layer embedded in a flexible medium, with a line-defect by removing three air holes for nanoscale structural deformation detection is proposed and optimized The cavity can hold the photonic band-gap modes with the fundamental mode located at approximately 686 nm, overlapping with the photoluminescence spectrum of the InGaP/InGaA1P quantum wells. Results of finite difference time-domain simulations indicate that the L3 cavity features an ultra-compact mode volume of 10(-3) mu m(3) and high quality factor of 10(4) at a sub-micron footprint within the studied visible wavelength. Theoretical optical strain sensitivities of approximately 4.5 and 3 nm per epsilon (1% strain for both) for the x and y directions are predicted, respectively. When the cavity is under large bending curvatures, the Q factor rapidly decreases from 8000 to 2000. (C) 2017 Optical Society of America