  A simple technique for observing optically stimulated electron paramagnetic
resonance (OSEPR) is proposed and investigated. The versatility and information
content of the described technique is demonstrated by the example of the OSEPR
spectra of systems that are unpopular for this type of spectroscopy: a crystal
with rare-earth ions Nd$^{3+}$ and a doped semiconductor GaAs. In addition, the
OSEPR spectrum of atomic cesium is presented, in which an optical nonlinearity
is observed that makes it possible to estimate the Rabi frequency for the
relevant optical transition. The effects observed in the described experiments
(switching of peaks to dips, light-induced splitting of the OSEPR lines, and
the appearance of a spectral feature at the double-Larmor frequency) are
interpreted using the model proposed in the theoretical part of the work. The
suggested interpretation shows the possibility of using the described OSEPR
technique to estimate not only `magnetic' parameters of the model Hamiltonian
(g-factors, spin relaxation times), but also the Rabi frequencies
characterizing optical transitions.
