Theoretical study of TiO2 based UV–VIS spectrometer gratings for assessment of skin lesions in localized scleroderma

• Published in: Optik (Stuttgart) 2022-11, Vol.270, p.170033, Article 170033
• Main Authors: Ravindran, Ajith, Nirmal, D., Pinkymol, K.P., Prajoon, P., Ajayan, J., Chander, Subhash
• Format: Article
• Language: English
• Subjects: Diffraction gratings; MEMS; Optical materials; Skin lesions; Spectroscopy
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2022.170033

Reflectance Spectroscopy is a helpful device to evaluate the seriousness of hyperpigmentation and erythema in Local scleroderma lesions. This article highlight the design of one dimensional regular grating comprised of TiO2 for the detection of skin lesions in localized scleroderma. The grating structure establishes the wavelength-dependent diffraction performance and it is required to theoretically recognize the optimum parameter for each application. The purpose of this study is to suggest a suitable grating with optimum parameters for assessing skin lesions. In order to analyze the best material and grating parameters for the detection of skin lesions, we simulated grating structure with different materials namely SiO2, SiN, Si3N4 and TiO2 by employing the appropriate factors, notably the Index of refraction, groove density and thickness. The numerical simulation is carried out with the help of COMSOL Multiphysics, and the finite element technique is used to model the reflection related properties of SiO2, SiN, Si3N4 and TiO2 based fixed gratings. The quantity of hemoglobin (erythema) and melanin (hyperpigmentation) is measured in terms of erythema index (EI) and also melanin index (MI). After optimizing geometric parameters, the designed grating achieved. an efficiency of 95.45%. The calculated reflectance, spectral resolution, efficiency, EI and MI of TiO2 based gratings are much higher than the similar geometry made up of other similar materials. The strong reflectance of TiO2 and its high efficiency of 95.45% in the wide range of 200–800 nm made the proposed structure very reliable for skin lesions detection. •Investigation of suitable grating for UV–VIS Spectrometer for assessment of Skin Lesions in Localized Scleroderma.•Electromagnetic waves frequency domain interface is used to model wave propagation in one grating unit cell and Floquet periodicity is used for simulation.•In the region of 200–800 nm Indium TiO2 based grating is suitable for reflecting type UV–VIS spectrometer grating that can be used for skin lesions detection.•The designed TiO2 based grating achieved a efficiency of 95.45% and can be a reliable prospect for skin lesions detection.