In this paper, we report on the measurement of the optical properties (absorption and scattering coefficients) of photoluminescent turbid media using a homemade integrating sphere setup equipped with a tunable monochromatic light source. The hemispherical reflectance and transmission data are analyzed with the radiative transfer equation using a Monte Carlo simulation-based lookup table to obtain the optical properties of the sample. The results are compared with the optical properties received from a classical integrating sphere setup equipped with a broadband white light source. The additional light of the photoluminescence generates artifacts within the optical properties, which are not present using a monochromatic light source. Additionally, a batch of samples with a broad range of scattering coefficients and dye concentrations were prepared and characterized with the aforementioned setup. The findings can help to generate a digital twin with the optical properties of the sample, which improves the physically based rendering and the design of, e.g., white-light LEDs. Dental restoration and photodynamic therapy also benefit from determination of the optical properties of photoluminescent turbid media.

Accurate determination of the quantum yield (${\mathrm{\Phi }}_f$) in scattering media is essential for numerous scientific and industrial applications, but it remains challenging due to re-absorption and scattering-induced biases. In this study, we present a GPU-accelerated Monte Carlo simulation framework that solves the full fluorescence radiative transfer equation (FRTE), incorporating spectrally dependent absorption, scattering, and fluorescence cascade processes. The model accounts for re-emission shifts, energy scaling due to the Stokes shift and implements a digital optical twin of the experimental setup, including the precise description of the applied integrating sphere. Using Rhodamine 6G in both ethanol and PDMS matrices, we demonstrate the accuracy of the method by comparing simulated reflectance and transmission spectra with independent experimental measurements. ${\mathrm{\Phi }}_f$ and emission distributions are optimized using a Levenberg–Marquardt algorithm. The obtained quantum yields agree well with literature values for Rhodamine 6G. This approach eliminates the need for empirical correction factors, enabling the reliable determination of actual, undistorted emission spectra and the ${\mathrm{\Phi }}_f$ in complex scattering media.

Optimizing phosphor-converted light-emitting diodes is challenging due to the complex interplay of absorption, elastic scattering and luminescence. Unlike previous studies that focused on characterizing optical parameters, this work isolates their individual contributions in order to derive fundamental design limits. We present a comprehensive analysis using a GPU-accelerated Monte Carlo framework that solves the luminescent radiative transfer equation, including the full luminescence cascade. We systematically investigate the influence of the absorption (${\mu }_a$) and scattering (${\mu }_s$) coefficients by varying them over a range of 0.1 to 10 times the reference values of a standard phosphor (0.8 wt%). We found that transmitted luminescence saturates when absorption exceeds approximately three times the reference value (${\mu }_a\approx 1.2{\mathrm{mm}}^{-1}$) and peaks at an optimal ${\mu }_s$ before backscattering losses dominate. In high-concentration regimes, mirror-assisted geometries are shown to enhance backward emission by a factor of 2.1 compared to open boundaries. Our findings provide model-based predictions for luminescence transport in phosphor–polymer composites.