We discuss a simple, experimentally feasible scheme, which elucidates the p
rinciples of controlling the reservoir spectrum and the spectral broadening
incurred by repeated measurements. This control can yield either the inhib
ition (Zeno effect) or the acceleration (anti-Zeno effect) of the quasiexpo
nential decay of the observed state by means of frequent measurements. In t
he discussed scheme, a photon is bouncing back and forth between two perfec
t mirrors, each time passing a polarization rotator. The horizontal and ver
tical polarizations can be viewed as analogs of an excited and a ground sta
te of a two level system (TLS). A polarization beam splitter and an absorbe
r for the vertically polarized photon are inserted between the mirrors, and
effect measurements of the polarization. The polarization angle acquired i
n the electrooptic polarization rotator can fluctuate randomly, e.g., via n
oisy modulation. In the absence of an absorber the polarization randomizati
on corresponds to TLS decay into an infinite-temperature reservoir. The non
-Markovian nature of the decay stems from the many round trips required for
the randomization. We consider the influence of the polarization measureme
nts by the absorber on this non-Markovian decay, and develop a theory of th
e Zeno and anti-Zeno effects in this system.