Sandilands Luke J, Cameron Thomas
Appl Opt. 2023 Oct 10;62(29):7700-7705. doi: 10.1364/AO.497962.
The impact of a finite thickness integrating sphere port on the measurement of diffuse reflectance is addressed in a combined numerical and experimental study. It is shown that for a finite thickness port, additional light losses occur due to scattering between the sphere port wall and the test sample, causing the sample reflectance to be underestimated. Monte Carlo ray tracing is applied to obtain quantitative estimates of the resulting measurement error for the case of a diffusely reflecting sample. The effects of sample reflectance, port geometry, and illumination beam size on the measurement error are explored. Experimental data collected with a pair of integrating sphere reflectometers with different port geometries support the validity of the numerical results. It is argued that finite port thickness may be an important source of measurement error, even for a well-designed integrating sphere port, and a strategy for minimizing this error is discussed.
在一项结合数值模拟和实验研究中，探讨了有限厚度积分球端口对漫反射测量的影响。结果表明，对于有限厚度的端口，由于球端口壁与测试样品之间的散射会产生额外的光损失，导致样品反射率被低估。应用蒙特卡罗光线追踪法来定量估计漫反射样品情况下产生的测量误差。研究了样品反射率、端口几何形状和照明光束尺寸对测量误差的影响。用一对具有不同端口几何形状的积分球反射仪收集的实验数据支持了数值结果的有效性。有人认为，即使对于设计良好的积分球端口，有限的端口厚度也可能是测量误差的一个重要来源，并讨论了将这种误差降至最低的策略。
