An optoacoustic probe including an ultrasound transducer array, an acoustic lens and a light path separated from the transducer array by an isolator to mitigate light energy from the light path from reaching the transducer array. The isolator can be formed from a mixture including a carrier material and between 10% and 80% by volume micro-bubbles. The isolator can be adapted to absorb, reflect or scatter light energy and absorb the optoacoustic response to light energy. In an embodiment, an optoacoustic probe also comprises an optical window and/or a diffuser, the isolator also separating the transducer array from these components.