  The quantum harmonic oscillator with parity-time ($\mathcal{PT}$) symmetry,
obtained from the ordinary (Hermitian) quantum harmonic oscillator by an
imaginary displacement of the spatial coordinate, provides an important and
exactly-solvable model to investigate non-Hermitian extension of the Ehrenfest
theorem. Here it is shown that transverse light dynamics in an optical
resonator with off-axis longitudinal pumping can emulate a
$\mathcal{PT}$-symmetric quantum harmonic oscillator, providing an
experimentally accessible system to investigate non-Hermitian coherent state
propagation.
