1：Experimental Design and Method Selection:

The study used confocal fluorescence microscopy and spectroscopy to analyze fluorescence from PMMA films and dielectric substrates. Methods included raster-scan imaging, hyperspectral mapping, time-correlated fluorescence, second-order fluorescence coherence, and fluorescence excitation spectroscopy at room and cryogenic temperatures (3.1 K).

2：1 K). Sample Selection and Data Sources:

2. Sample Selection and Data Sources: Samples included bare fused silica, quartz, sapphire substrates, and PMMA films spin-coated on these substrates using various solvents (anisole, chlorobenzene, methyl isobutyl ketone, toluene). Substrates were cleaned with acetone, isopropanol, deionized water, and oxygen plasma. PMMA films were prepared with specific molecular weights and solvents, with thickness adjusted to 200 nm using an ellipsometer.

3：List of Experimental Equipment and Materials:

Equipment included a home-built confocal microscope, objectives with numerical apertures of 0.65, 0.82, and 1.30, helium bath cryostat, closed-cycle cryostat, continuous-wave laser at 532 nm, ps-excitation laser, optical parametric oscillator, supercontinuum laser, single photon counting avalanche photodiodes, monochromator with CCD, scanning Fabry-Pérot etalon. Materials included PMMA resins, solvents (e.g., anisole, chlorobenzene), and dielectric substrates (fused silica, quartz, sapphire, silicon nitride membranes).

4：65, 82, and 30, helium bath cryostat, closed-cycle cryostat, continuous-wave laser at 532 nm, ps-excitation laser, optical parametric oscillator, supercontinuum laser, single photon counting avalanche photodiodes, monochromator with CCD, scanning Fabry-Pérot etalon. Materials included PMMA resins, solvents (e.g., anisole, chlorobenzene), and dielectric substrates (fused silica, quartz, sapphire, silicon nitride membranes). Experimental Procedures and Operational Workflow:

4. Experimental Procedures and Operational Workflow: Substrates were cleaned and coated with PMMA via spin-coating. Fluorescence maps were acquired by raster-scanning samples under laser excitation, with intensity and spectral data recorded. Cryogenic experiments were conducted at 3.1 K, and polarization, time-resolved, and photon correlation measurements were performed to characterize emitter properties.

5：1 K, and polarization, time-resolved, and photon correlation measurements were performed to characterize emitter properties. Data Analysis Methods:

5. Data Analysis Methods: Data analysis included Gaussian fitting of spectra, correlation analysis for vibrational modes, exponential fitting for fluorescence decay, and statistical analysis of photon antibunching using second-order coherence functions.