We report the direct observation of conductivity modulation by heavy‐to‐light hole transitions inp‐type germanium. The resistance of ap‐type germanium bar was modulated by microsecond pulses of 10‐&mgr; radiation from aQ‐switched CO2laser. An estimate of the fast carrier lifetime is 10−12sec. Direct observation of 20‐Mc ringing on the laser pulse is reported. The band‐to‐band type of transition permits room temperature operation.