Photonic Localization Techniques” is about die level analysis techniques based on electroluminescence effects of functional anomalies in the DUT. Photon Emission, the most important functional analysis technique in micro- and nanoelectronics to localize active device performance and anomalies, is presented in theory and application. Starting with - The fundamental physics behind the phenomena to understand the functional origin of the light emission in the device, and a - Classification of the effects in various device operation modes, over - Specialities for application through chip backside, to - Dynamic application in Time Resolved Emission (TRE) or PICA techniques, all the important issues will be covered. An outlook of the challenges and opportunities with future technologies will be given with respect to optical resolution, spectral and low voltage issues. References to complementary techniques like laser stimulation techniques and thermographic techniques will be given.