Highly efficient elliptical microcavity refractive index sensor with single detection unit

Abstract

Here, an elliptical cavity is investigated in its vertical and horizontal arrangement as a single detection unit in a 2D hexagonal hole-type photonic crystal. The Q-factors are 3700, and 2600 for vertical and horizontally arranged cavities, respectively. The notable characteristic of the presented sensor is mainly its large detection range for refractive indices in range of n = 1 to over 2. The operation of the sensor can be divided into two distinct detection regions in separate spectra located next to lower and higher edges of photonic band gap. The design of cavities and their sensing characteristics are discussed in detail for each topology using FDTD and PWE methods.