Hello Jing,

Thanks for your questions here!

The Quantum Yield spectrum is the efficiency of the down conversion process, but it does not intrinsically take into account the effect of down conversion on the ray intensity. The wavelength shift’s effect on intensity is calculated by OpticStudio by multiplying the quantum yield value by the ratio of the incident and emitted wavelengths, known as the Stokes shift:

I_Emitted = I_Incident * A * Q * (λ_Incident / λ_Emitted) = I_Absorbed * Q * (λ_Incident / λ_Emitted)

where A is the absorption coefficient and Q is the quantum efficiency. So, Q is the internal quantum yield, and A*Q would be the external.

You may find more information about the Spectrum Files and Quantum Yield in the Help files at:

The Setup Tab > Editors Group (Setup Tab) > Non-sequential Component Editor > Object Properties (non-sequential component editor) > Volume Physics > Phosphors & Fluorescence

Besides, further references can be found in the following knowledgebase articles:

Overview of photoluminescence simulation in OpticStudio

Modeling Photoluminescence in OpticStudio: A Photoluminescent Solar Concentrator

If you have any further questions, please let us know and we will be happy to help!

Best,

Csilla