This mini-paper presents a geometric interpretation of sonoluminescence within USP Field Theory. Ultrasonic driving sustains a macroscopic Δf mismatch in water, while dissolved gas nucleates a weakly locked cavity. During collapse, geometric focusing amplifies the local mismatch beyond a molecular damping threshold, activating electronic corridors and releasing light. The model: Preserves standard bubble dynamics (Rayleigh–Plesset / Keller–Miksis) Introduces Δf(t) and χ(t) as geometric overlays Explains broadband spectra and ultrashort flash duration without plasma or extreme temperature assumptions Connects engineered sonoluminescence to biological cavitation (e.g., pistol shrimp) Shows conceptual continuity with cosmic Δf-collapse (CMB resonance floor) No new forces or exotic particles are introduced—only resonance geometry and mismatch focusing. Related USP Documents msf:48000 — CMB as Δf resonance floor msf:49810 — Deterministic photon fate msf:47650 — Δf corridor decay geometry