FOS: A fully integrated open-source program for Fast Optical Spectrum calculations of nanoparticle media

FOS, which means light in Greek, is an open-source program for Fast Optical Spectrum calculations of nanoparticle media. This program takes the material properties and a description of the system as input, and outputs the spectral response including the reflectance, absorptance, and transmittance. Previous open-source codes often include only one portion of what is needed to calculate the spectral response of a nanoparticulate medium, such as Mie theory or a Monte Carlo method. FOS is designed to provide a convenient fully integrated format to remove the barrier as well as providing a significantly accelerated implementation with compiled Python code, parallel processing, and pre-trained machine learning predictions. This program can accelerate optimization and high throughput design of optical properties of nanoparticle or nanocomposite media, such as radiative cooling paint and solar heating liquids, allowing for the discovery of new materials and designs. FOS also enables convenient modeling of lunar dust coatings, combustion particulates, and many other particulate systems. In this paper we discuss the methodology used in FOS, features of the program, and provide four case studies.

FOS（希腊语中意为“光”）是一款用于纳米颗粒介质快速光谱（Fast Optical Spectrum）计算的开源程序。该程序以材料特性和系统描述为输入，输出包含反射率、吸收率与透射率在内的光谱响应。以往的开源代码通常仅涵盖计算纳米颗粒介质光谱响应所需的部分功能，例如米氏理论（Mie theory）或蒙特卡罗方法（Monte Carlo method）。FOS旨在提供便捷的全集成格式以消除这一障碍，并通过编译型Python代码、并行处理及预训练机器学习预测实现显著加速。该程序可推动纳米颗粒或纳米复合材料介质（如辐射冷却涂料与太阳能加热液体）光学特性的优化与高通量设计，助力新型材料与设计方案的发现。此外，FOS还支持对月尘涂层、燃烧颗粒及其他多种颗粒系统的便捷建模。本文将探讨FOS所采用的方法、程序特性，并呈现四个案例研究。