Surface optimization and synergistic quantification method for OTS anti-relaxation coatings
Yian Xu, Hao Xia, Jiale Quan +5 more
To enhance the anti-relaxation performance of alkali metal vapor cells in quantum sensors, a synergistic optimization and quantitative evaluation strategy for surface parameters of octadecyl-trichlorosilane (OTS) anti-relaxation coatings is proposed. By systematically adjusting solution concentration and reaction time, both the polarization retention angle and the surface polarization retention cross-section are effectively optimized, achieving a maximum retention angle of 135°. A theoretical framework is subsequently established to quantify adsorption energy based on the inherent correlation between these two surface parameters. A correction method for the retention cross-section, developed through a non-uniform wetting model, enables in-situ mapping of the kinetic contribution to adsorption behavior. Through kinetic and thermodynamic parameter extraction, the adsorption energy and Gibbs free energy of the multilayer OTS coatings are determined to be 0.13 eV, which represents a substantial reduction compared to the adsorption energy of bare glass surfaces, previously reported as 2.01 eV. Furthermore, longitudinal relaxation time measurements are carried out inside vapor cells, yielding a maximum collision count of 593, which provides strong evidence of polarization preservation capability. This approach provides both theoretical guidance and an experimental pathway for optimizing coating performance and analyzing adsorption mechanisms, thereby facilitating the development of high-performance alkali metal vapor cell materials for quantum sensing applications. • Synergistic optimization of OTS coating parameters improved polarization retention, achieving a maximum retention angle of 135° by adjusting solution concentration (2-6 mM) and reaction time (60-120 min). • A heterogeneous wetting-based synergy quantification method is developed, enabling accurate evaluation of multilayer formation and local adsorption behavior by jointly analyzing retention angle and retention cross-section. • A combined thermodynamic-kinetic modeling framework establishes quantitative correlations between adsorption energy, Gibbs free energy, and coating surface characteristics, providing theoretical guidance for anti-relaxation material design. • Longitudinal relaxation tests in coated vapor cells demonstrate a maximum collision count of 593, confirming suppressed alkali-atom adsorption and strong polarization preservation consistent with the low adsorption energy of 0.13 eV.
Defence Technology•Apr 25, 2026•0 citations