Spectro‐Temporal Ratiometric Strategy for Thermally Invariant Optical Manometry

ABSTRACT Optical manometry provides noncontact pressure sensing but remains vulnerable to temperature‐induced drift, where thermal expansion and nonradiative relaxation distort luminescence spectra and kinetics. We develop a spectro‐temporal ratiometric approach that combines spectral and time‐gated luminescence channels to decouple pressure and temperature responses and realize thermally invariant optical manometry. Using Y 3 In 2 Ga 3 O 12 :Cr 3+ as a rigid‐lattice host (D q/B ≈ 2.2), lattice stiffness minimizes thermal sensitivity S R,T , while ratiometric detection stabilizes pressure sensitivity S R,p . The resulting thermal‐invariance manometric factor ( TIMF) = S R,p / S R,T reaches ≈7700 K·GPa −1 in the spectral domain and ≈2500 K·GPa −1 in the time‐gated domain, with S R,p up to 51%·GPa −1 . These values exceed ruby benchmarks by two orders of magnitude and surpass conventional lifetime analysis by ∼40 times, enabling accurate, self‐referenced optical pressure mapping under extreme thermo‐mechanical conditions. This work provides luminescent manometry from empirical calibration to a quantitative framework for thermally reliable sensing in coupled fields.