High effective sensors based on photonic crystals

Abstract

Photonic crystals have been extensively studied as high effective sensors for environmental monitoring and chemical and biological detections. This paper reviews recent achievements on photonic crystal sensors. Especially, the band gap responsiveness and the ability in amplifying spontaneous emission are demonstrated in the reported photonic crystal monitors/sensors. They are of great importance for optical monitors/sensors visualized by the naked eye and sensors based on fluorescence applications. The photonic crystal sensors are promising for low-cost and high effective sensors and detection methods, although challenges still exist in practical applications.

Simple, efficient and accurate method toward the monitoring of ethyl butanoate traces

“…For others who are suffering from some diseases like lung cancer, liver diseases, lung diseases and COVID 19, some gases like toluene, isoprene and ethyl butanoate (EB) are present within the dry exhaled breath (Chen et al 2020 ; Boots et al 2014 ; Tangerman et al 1983 ; Szulejko et al 2010 ). In this context, the effective refractive index of the dry exhaled breath is depending on the refractive indices of these gases and their volume fractions as well according to the following relation (Li and Song 2010 ; Zhang et al 2008 ; Haynes 2017 ; White and Fan 2008 ; Beheiry et al 2010 ; Wu et al 2013 ): where n and V represent the refractive indices and volume fractions of the different gases, respectively. Figure 5 shows the dependence of the effective refractive index on the wavelength of the incident EM waves at different values of ethyl butanoate concentrations.…”

“…3 The reflectance spectrum of our design as a thin layer of Au with thickness = 10 nm is deposited over the 1D PCs 19, some gases like toluene, isoprene and ethyl butanoate (EB) are present within the dry exhaled breath (Chen et al 2020;Boots et al 2014;Tangerman et al 1983;Szulejko et al 2010). In this context, the effective refractive index of the dry exhaled breath is depending on the refractive indices of these gases and their volume fractions as well according to the following relation (Li and Song 2010;Zhang et al 2008;Haynes 2017;White and Fan 2008;Beheiry et al 2010;Wu et al 2013):…”

Detection of isoprene traces in exhaled breath by using photonic crystals as a biomarker for chronic liver fibrosis disease

“…In the case of liver fibrosis disease, the levels of isoprene (ppm) are increased in the exhaled breath of unhealthy persons [5]. The effective refractive index (n eff ) of the dry exhaled breath is obtained by the rule of the mixture as [32]:…”

Thiourea functionalized hydrogel photonic crystal sensor for Cd2+ detection

“…Photonic crystals (PCs) are materials where the refractive index is periodically modulated on a length scale comparable to the light wavelength of interest, from which forms the photonic bandgap. 1,2 Hydrogels are soft materials, mainly composed of water, that can undergo volume-phase transitions in which their volume shrinks or swells in response to certain stimuli. 3,4 When the periodic three-dimensional (3D) structure of PCs is integrated with hydrogels, the swelling/deswelling behavior of the hydrogels can lead to significant shifts in the Bragg diffraction wavelength of PCs, thus creating hydrogel photonic crystal (HPC) materials with tunable optical properties.…”

“…5 HPC materials open a new door to tune the photonic properties and offer promise in applications that do not require complete photonic bandgaps, such as chemical/biological sensors. 1,3,[5][6][7][8][9][10][11][12] Incorporation of functional organic molecules could alter or enhance the properties of the HPC sensor. Recent research works have focused on functionalized PC structures to exploit their remarkable properties for wider applications.…”