Biosensors based on novel nonlinear delta-function photonic crystals comprising weak nonlinearities

Enhancement of absorption in a CH3NH3PbI3-based photonic crystal in the presence of the monolayer MoS2

Using the transfer matrix approach, we investigate theoretically the absorbance, transmittance, and reflectance through one-dimensional CH₃NH₃PbI₃ perovskite-based photonic crystal at room temperature. In our proposed structure, a monolayer MoS₂ film is embedded between two CH₃NH₃PbI₃ layers. We found that, the presence of monolayer MoS₂ film increases the absorbance in longer wavelengths [Formula: see text] With increasing the number of periods, absorbance increases in most wavelengths of the incident light. It was shown that, by controlling the number of periods, the absorbance coefficient can be tuned according to the wavelength and angle of incident light. Furthermore, for incident light with longer wavelength, the absorbance, transmittance as well as reflectance versus thickness of the perovskite layer have an oscillatory behavior, and with increasing the number of periods this oscillatory behavior becomes more obvious and prominent. For the incident light in the infrared region, by increasing the number of periods the absorbance as opposed to the transmittance increases for different incidence angles. While, the reflectance coefficient first shows oscillatory behavior by increasing the number of periods, then with a further increase in the number of periods it reaches a constant value. The proposed structure can be useful for optoelectronic and optical devices. Such as improving the efficiency of solar cells based on the hybrid inorganic-organic perovskites and infrared sensor system.

SARS-CoV-2 detecting rapid metasurface-based sensor

We have proposed a novel approach to detect COVID-19 by detecting the ethyl butanoate which high volume ratio is present in the exhaled breath of a COVID-19 infected person. We have employed a refractive index sensor (RIS) with the help of a metasurface-based slotted T-shape perfect absorber that can detect ethyl butanoate present in exhaled breath of COVID-19 infected person with high sensitivity and in-process SARS-CoV-2. The optimized structure of the sensor is obtained by varying several structure parameters including structure length and thickness, slotted T-shape resonator length, width, and thickness. Sensor's performance is evaluated based on numerous factors comprising of sensitivity, Q factor, detection limit, a figure of merit (FOM), detection accuracy, and other performance defining parameters. The proposed slotted T-shape RIS achieved the largest sensitivity of 2500 nm/RIU, Q factor of 131.06, a FOM of 131.58 RIU^-1, detection limit of 0.0224 RIU.