Photons have no charge. Light is a form of electromagnetic energy.
All spectroscopic effects (to my knowledge) are due to changes in electron state, induced either through an interior or exterior EM (Electro-Magnetic) field. EM forces may affect that state, which in turn affects the light emitted during the change of state, e.g. the Zeeman effect, etc.
However, if we exclude all such spectroscopic phenomena, and consider EM fields purely energetically on the one side, and light energy on the other, are there any know direct effects of EM fields on light itself?
(I'd really like to hear from physicists with hands on knowledge - and please keep all the Tags as is because I have reasons for selecting them, thx.)