  Landauer's erasure principle is a cornerstone of thermodynamics and
information theory. According to this principle, erasing information incurs a
minimum energy cost. Recently, Vaccaro and Barnett [Proc. R. Soc {\bf 467},
1770 (2011)] explored information erasure in the context of multiple conserved
quantities and showed that the erasure cost can be solely in terms of spin
angular momentum. As Landauer's erasure principle plays a fundamental role in
heat engines, their result considerably widens the possible configurations that
heat engines can have. Motivated by this, we propose here a novel optical heat
engine that operates under a single thermal reservoir and a spin angular
momentum reservoir coupled to a three level system with an energy-degenerate
ground state. The proposed heat engine operates without producing waste heat
and goes beyond the traditional Carnot engine where the working fluid is
subjected to two thermal baths at different temperatures.
