Fabrication and characterization of porous tissue-mimicking optical phantoms as a tool for optical sensor validation

Abstract

This paper presents porous polydimethylsiloxane (PDMS) optical phantoms with tunable microstructural and optical properties to mimic porous biological tissues (e.g., fruit) during the design and optimization of novel optical setups. A well connected salt network formed using salt particles of various size distributions was used to obtain porous PDMS phantoms of different porous features including porosity, pore size distribution, pore number density and pore connectivity. These microstructural features are strongly related to the light scattering from the phantom where a higher reduced scattering coefficient ( ${\mu }_s^{\text{'}}$ ) was observed from the porous PDMS phantom with a higher number of small pores compared to the optical phantom with a lower number of larger pores. The prepared phantoms were used to validate GASMAS (gas in scattering media absorption spectroscopy) H₂ O and O₂ sensors by quantifying the optical path length through the pores and the O₂ concentration inside the pores.

Keywords: GASMAS; PDMS; microstructural properties; optical properties; porous optical phantom.