Refractive index sensing of gases based on a one-dimensional photonic crystal nanocavity

Abstract

Abstract. Silicon photonic crystal sensors have become very attractive for various optical sensing applications. Using silicon as a material platform provides the ability to fabricate sensors with other photonic devices on a single chip. In this paper, a new optical sensor based on optical resonance in a one-dimensional silicon photonic crystal with an air defect is theoretically studied for refractive index sensing in the infrared wavelength region. The air defect introduces a cavity into the photonic crystal, making it suitable for probing the properties of a gas found within the cavity. This photonic crystal nanocavity is designed to oscillate at a single mode with a high quality factor, allowing for refractive index sensing of gases with a high sensitivity. A method is presented to maximize the sensitivity of the sensor and to obtain a very narrow bandwidth cavity mode for good sensor resolution. We change the thickness of the air layers linearly in the photonic crystals on both sides of the nanocavity and show that a sensitivity of 1200 nm RIU −1 can be achieved. We present a detailed analysis of the sensor and variations of the layer thicknesses, the cavity length, and the number of periodic layers in the photonic crystal are investigated. This optical sensor has a much simpler design and higher sensitivity compared to other photonic crystal sensors reported previously.

Transmission and Thermal Emission in the NO2 and CO Absorption Lines using Macroporous Silicon Photonic Crystals with 700 Nm Pitch

“…Several articles have dealt with this issue in 1D and 2D PCs -i.e. (Alvarado-Rodriguez 2003;Xiao et al 2016;Mohebbi 2015). However, the influence of the defects morphology in the optical response of 3D photonic crystals have not been so deeply analysed, perhaps, because of the high dependence of the method used to fabricate the PC (Nelson 2011;Braun et al 2006b).…”

High-Sensitive Thermal Sensor Based on a 1d Photonic Crystal Microcavity With Nematic Liquid Crystal

“…In recent years, their applications as a sensor based on the structure of liquid crystal photonic crystal have experienced a growing development; these rapid developments in photonic technology have greatly improved the efficiency of detection, particularly in the areas of light-liquid interaction and system miniaturization. Any of these optical sensors measure optical property differences as a result of a difference in the refractive index and the material width of a liquid or gas [16].…”

“…It is necessary for certain photonic devices operating in the infrared region to understand the N-LC refractive indices in this light region. The layers of selected materials are used in the present structure to achieve high contrast between the high refractive index of the layers and to provide a high optical field in the central microcavity [16]. In order to potentially use the given structure as a thermal sensor, the microcavity is modified with different values of defect width W Lc .…”

Refractive Index Sensor Based on Micro- Structured Optical Fibers with Using Finite Element Method

“…Optical fiber sensors have wide applications in science, the environmental monitoring, and communication technology this is due to their compact in size, high sensitivity, electrical passiveness, immune to electromagnetic interference, wide bandwidth as well be made convenient for tip-based sensing. Most of these optical sensors measure the variations of optical properties because of a change in the refractive index (RI) of a gas or a liquid [1]. Measuring the RI of fluids is very important; so as to depict the optical properties of fluids which is lead to evolution of RI sensors for applying in many fields such as the salinity of water measurement [2], and biotechnology processes [3] also provide important acquaintance on drug/DNA interaction and growth of the cell [4].…”