Pressure distribution imaging through wide-field optical detected magnetic resonance

Non-hydrostatic stress plays a significant role in shaping the properties of materials under compression. High-pressure effects such as yielding deformation, phase transitions, and volume contraction can alter the pressure distribution within the pressure chamber. However, due to the inherent size limitation of the diamond anvil cell (DAC), in situ high-pressure studies usually assume a hydrostatic environment, equaling the pressure of samples to a pressure calibrator inside the chamber. Accurately imaging pressure distribution within the DAC chamber remains challenging, particularly as the material undergoes phase transitions. Here, we present a method for mapping pressure distribution with high spatial resolution using wide-field optically detected magnetic resonance (ODMR) of nanodiamonds. The pressure gradients during the high-pressure transition of zinc oxide (ZnO) were compared using both the multiple rubies technique and wide-field ODMR. The latter technique demonstrated superior spatial resolution, easier operation, and more detailed information. These results highlight the potential of wide-field ODMR as a powerful tool for precise pressure sensing, particularly in studies involving non-hydrostatic pressure conditions.