Abstract: This paper presents an innovative experimental instrument using a liquid-core cylindrical lens. The instrument aims to enhance university-level experimental teaching, scientific research, and student innovation in optical measurement applications. Based on a self-designed liquid-core cylindrical lens, the instrument combines methods like the equal-refractive-index thin-layer movement, Boltzmann-Matano, and transient image analysis to achieve rapid, high-precision measurement of liquid refractive indices and liquid-phase diffusion coefficients. Experimental results show that the instrument offers a refractive index measurement accuracy of over 0.0002 RIU and a liquid-phase diffusion coefficient measurement deviation of under 0.02×10-5 cm2/s. It also provides strong anti-interference, short measurement time, and a visual process. Fifteen supporting experimental courses have been developed. These enable students to dynamically observe and numerically simulate processes from optical path adjustment and eliminating spherical aberration to diffusion and dissolution. The instrument is a highly efficient and reliable tool for scientific research and teaching and has broad application prospects.

Key words:  liquid diffusion coefficient measuring instrument, liquid-core cylindrical lens, liquid refractive index, liquid-phase diffusion coefficient