Nanodiamonds enable adaptive-optics enhanced, super-resolution, two-photon excitation microscopy

Particles of diamond in the 5 to 100 nm size range, known as nanodiamond, have shown promise as robust fluorophores for optical imaging. We demonstrate here that, due to their photo-stability, they are not only suitable for two-photon imaging, but they allow significant resolution enhancement when combined with computational super-resolution techniques. We observe a resolution of 42.5 nm when processing two-photon images with the Super-Resolution Radial Fluctuations algorithm. We show manipulation of the point-spread function of the microscope using adaptive optics. This demonstrates how the photostability of nanodiamond can also be of use when characterising adaptive optics technologies or testing the resilience of super-resolution or aberration correction algorithms.