1：Experimental Design and Method Selection:

The study involved preparing codoped glass samples with varying concentrations of Er3+ and Dy3+ to investigate energy transfer mechanisms. Absorption, excitation, and emission spectra were measured, and time-resolved spectroscopy was used to analyze decay times. Theoretical models for energy transfer efficiency were applied.

2：Sample Selection and Data Sources:

Glass samples were prepared with a composition of 80%PbGeO3:10%PbF2:10%CdF

3：Two codoped sample groups were made:

one with fixed Er3+ concentration (0.50 mol%) and varying Dy3+ (0.25, 0.50, 0.75 mol%), and another with fixed Dy3+ concentration (0.75 mol%) and varying Er3+ (0.25, 0.50, 0.75 mol%). Single-doped samples with 1.0 mol% Er3+ and 1.0 mol% Dy3+ were also prepared.

4：50 mol%) and varying Dy3+ (25, 50, 75 mol%), and another with fixed Dy3+ concentration (75 mol%) and varying Er3+ (25, 50, 75 mol%). Single-doped samples with 0 mol% Er3+ and 0 mol% Dy3+ were also prepared. List of Experimental Equipment and Materials:

3. List of Experimental Equipment and Materials: Equipment included a LAMBDA 1050 UV/VIS/NIR spectrophotometer (Horiba, Japan) for absorption measurements, a spectrofluorometer (TCSPC Nanolog, Horiba) for excitation spectra, a laser source at 405 nm (OBIS, Coherent) for luminescence, a fiber-integrated UV-VIS-NIR spectrograph (HR 4000, Ocean Optics) for emission spectra, and a time-resolved measurement system with a pulsed pump lamp (FL1040-1457B-3714, Horiba), spectrometer (iHR 320, Horiba), data acquisition module (SpectrAcq2, Horiba), and photomultiplier tube detector. Materials included the glass host and dopant ions.

5：Experimental Procedures and Operational Workflow:

Samples were excited at 405 nm, and emissions were collected. Absorption spectra were measured from 400 to 1800 nm. Excitation spectra were collected from 330 to 500 nm. Time-resolved measurements were performed for specific emission bands using bandpass filters. Lifetimes were calculated using the integral method for decay curves.

6：Data Analysis Methods:

Data were analyzed by normalizing emission spectra, measuring intensity changes, and calculating lifetimes and energy transfer efficiencies using statistical methods and software tools associated with the equipment.