High Mach number shock induced turbulent mixing of two gases of different densities is investigated in a double diaphragm shock tube. The study of shock‐accelerated interfaces between two fluids of different densities is known as the study of shock‐excited Rayleigh‐Taylor or Richtmyer‐Meshkov instability. In the present experiments, the gases are initially separated by a thin plastic membrane materializing the interface. Different measurement techniques have been used to observe the created turbulent mixing zone: infrared absorption of a CO2vibrational‐rotational line which provides average temperature and density profiles in the mixing zone, infrared emission of CO2which gives the evolution of the mixing zone thickness and Schlieren photographs which provide another measurement of the mixing zone thickness as well as qualitative informations on the three‐dimensional nature of the shock and turbulent mixing after interaction. Results are compared to similar experiments at high Mach number conditions.