A photo-conductive germanium hot-hole detector has been used to directly measure the cut-off time for transmission through a laser induced breakdown plasma. By employing a dust free atmosphere and controlled plasma initiation, the breakdown intensity was varied and its effect on the cut-off rapidity was investigated. The time taken for the transmitted signal to fall to half its initial value was found to be approximately inversely proportional to the breakdown intensity. This result is shown to be in agreement with conclusions reached by means of simple theory. © 1979.