Refractometric and temperature sensors based on one-dimensional binary photonic crystal including a superconducting layer

A refractometric and low-temperature sensor based on a simple one-dimensional binary photonic crystal is investigated. The photonic crystal consists of alternating layers of superconductor and air. The principle of operation of the proposed sensor is as follows: the refractive index of the air layer or the temperature is changed by a very small amount and the wavelength position of a specific point in the transmission spectrum is observed before and after the change. In the refractometric sensor, the sensitivity is calculated as SR = AX/An2 and in the temperature sensor as ST = AX/AT, where AX, An2 and AT are the change in the wavelength position of that point, change in the air refractive index and temperature change. The parameters of the superconducting layer are optimized to attain the highest sensitivity. The maximum sensitivities of the refractometric and temperature sensors are found as 485.438 nm/RIU and 1.05751 nm/K. The proposed structure is a multifunction sensor because the optical properties of a superconducting medium can be changed by varying the operating temper-ature, critical temperature and wave frequency. It can be used as a sensor for a broad range of cells in the field of biosensing.