Development of a high pressure diagnostic based on optical Raman backscatter measurements in diamond

High pressure diagnostics for pulsed power high energy density physics experiments require time-resolved measurements under shock loading conditions with pressures exceeding a megabar. A high pressure diagnostic based on the optical Raman spectrum in oriented crystalline diamond is discussed. By placing the diamond probe in a preferred crystallographic orientation, shock loading due to the pressure wave induces a crystal strain proportional to the applied stress. A strain induced optical frequency shift in the Raman spectrum of diamond is measured temporally with a streak camera to permit real time determination of the pressure wave amplitude. Diamond Raman should provide a first step in achieving a high pressure probe standard for shock loading conditions and large density compression studies exceeding megabar stresses.