We demonstrate that stimulated parametric emission (SPE) microscopy enables label-free, 3-D visualization of internal hemoglobin distribution of live mouse and chicken erythrocytes with high sensitivity. Change in hemoglobin distribution in chicken erythrocytes before and after ethanol fixation is clearly visualized.

The ability to perform high-resolution unstained live imaging is very important to in vivo study of cell structures and functions. Stimulated parametric emission (SPE) microscopy is a nonlinear-optical microscopy based on ultra-fast electronic nonlinear-optical responses. For the first time, we have successfully applied this technique to archive three-dimensional (3D) images of unstained sub-cellular structures, such as, microtubules, nuclei, nucleoli, etc. in live cells. Observation of a complete cell division confirms the ability of SPE microscopy for long time-scale imaging.