  We consider the correlation of the electromagnetic field to determine spatial
coherence inside a sonoluminescing bubble. We explicitly calculate the first
order correlation function for two limiting cases of the excitation field: a
blackbody spectrum and a discrete multifrequency spectrum. The correlation
length for blackbody fields at temperatures between 3000 K and 10000 K is found
to be on the order of the optical wavelength, increasing with decreasing
temperatures. We predict spectral lines in the emission spectrum of single
bubble sonoluminescence in cooler bubbles with interior temperatures below
10000 K.
