光物理学（optical physics）研究电磁辐射的生成与性质、电磁辐射与物质之间的相互作用，特别是其控制与操纵。它与一般光学、光学工程不同的方面是在于它比较专注于发现与应用新光学现象；但在光物理学、应用光学、光工程学之间，并没有太大的区别，因为光工程学所发展出来的组件、应用光学找到的实际用途，都是光物理学的基础研究所必需的前提，而这基础研究又导致发展出新组件与新用途。研究员时常会同时参与基础研究与应用发展的各种计划，例如，史蒂芬·哈瑞斯做实验发现了电磁感应透明现象，他又与莱娜·豪合作对于慢光（slow light）技术的发展贡献良多。

Optical physics is a subfield of atomic, molecular, and optical physics. It is the study of the generation of electromagnetic radiation, the properties of that radiation, and the interaction of that radiation with matter, especially its manipulation and control. It differs from general optics and optical engineering in that it is focused on the discovery and application of new phenomena. There is no strong distinction, however, between optical physics, applied optics, and optical engineering, since the devices of optical engineering and the applications of applied optics are necessary for basic research in optical physics, and that research leads to the development of new devices and applications. Often the same people are involved in both the basic research and the applied technology development, for example the experimental demonstration of electromagnetically induced transparency by S. E. Harris and of slow light by Harris and Lene Vestergaard Hau.