Distinct cases with varying gas-liquid hydrodynamic behaviors were analyzed, revealing that photon absorption is highly dependent on the specific conditions employed. Gas bubbles create gas-liquid interfaces that interact with photons, but their influence on photon absorption in the liquid was found to be less significant than initially anticipated based on the feed ratio (Figure and Figure ). Factors such as relatively low gas holdups, as well as reflection, refraction, and scattering, contribute to reducing photon absorption losses. The decrease in liquid residence time caused by the addition of a gas phase is counteracted by these effects, meaning that adding a gas phase does not require a proportional reduction in the liquid flow rate to maintain photon absorption at the same level.