We present experimental results that explore the degree to which metal-clad
microcavities may alter the spontaneous emission rate of a fluorescent spe
cies embedded within the cavity. We examine the role of the reflectivity an
d loss of the mirrors in determining the modified decay rate by altering th
e thickness of one of the metal mirrors. We show that despite losses arisin
g from the metallic mirrors, metal-clad microcavities may still significant
ly modify the spontaneous emission rate of the embedded emitter.