光子学（Photonics）是一种与光子相关的科学研究，包括光的产生、发射、传输、调制、信号处理、切换、放大及传感。光不单纯是粒子，也不只是波动，光兼具有二者的特性。光子学包括光从紫外线、可见光到远红外线之间所有频谱的应用。不过大部份的应用是在可见光及近红外线。光子学一词是在1960年代初期，第一个实用的半导体光传感器发明后，以及1970年代光纤发展之后开始出现。

光子能量吸收倍频该频率的以普朗克常数（h）代表。

Photonics is the science of light (photon) generation, detection, and manipulation through emission, transmission, modulation, signal processing, switching, amplification, and detection/sensing. Though covering all light's technical applications over the whole spectrum, most photonic applications are in the range of visible and near-infrared light. The term photonics developed as an outgrowth of the first practical semiconductor light emitters invented in the early 1960s and optical fibers developed in the 1970s.