  ALICE (A Large Ion Collider Experiment) at the LHC is designed for studies of
nuclear matter at extreme temperatures and energy densities, so called
Quark-Gluon Plasma (QGP). Two detectors for measurements of electromagnetic
signals, high-granularity photon spectrometer PHOS and large acceptance
electromagnetic calorimeter EMCal/DCal, are incorporated into the ALICE
apparatus. In order to enhance the data sample of the high-energy part of the
spectra, a dedicated triggers on high energetic photons or jets are used. High
precision measurements of neutral mesons require fine energy and timing
calibrations. Photon signal purity is improved using dedicated photon PID
criteria based on cluster shape and anti-track matching with the ALICE central
tracking system, as well as a special detector located in front of PHOS called
CPV. PHOS and EMCal participated in LHC Run 1 (2009-2013) and Run 2 (2015-2018)
during data taking periods of pp, p-Pb and Pb-Pb collisions. We give an
overview of their performance in Runs 1 and 2 in low and high multiplicity
environments as well as the upgrade plans for future LHC runs.
