This is going beyond my expertise, but I'll give an attempt at an answer. Take this with a massive grain of salt. It's almost certainly some level of wrong: Th

This is going beyond my expertise, but I'll give an attempt at an answer. Take this with a massive grain of salt. It's almost certainly some level of wrong: The trapped light does not take up physical space in the same way that matter does and can lead to an increase in the local energy density within the photonic crystal. However, it is not clear how this energy could be efficiently extracted and used for practical applications. Also, the confined light is subject to energy loss through various mechanisms, such as absorption by the material or scattering and these losses would limit the amount of energy that can be effectively stored in the system over time.