Using a random laser to measure the content of protein in skim milk

The luminescence of skim milk samples with distinct protein content doped with rhodamine B was investigated. The samples were excited by a nanosecond laser tuned at 532 nm, and the emission was characterized as a ran-dom laser. Its features were analyzed as a function of the protein aggregate content. The results showed a linear correlation between the random laser peak intensity and the protein content. This paper proposes a rapid detec-tion photonic method to evaluate the protein content in skim milk based on the intensity of the random laser emission.(c) 2023 Optica Publishing Group