Phase contrast and DIC illumination for AFM hybrids

High-resolution optical microscopy is an essential pre-requisite for life science force microscopy, particularly for applications in cell biology and medicine. Identification and validation of cells is typically established with techniques like phase contrast microscopy or differential interference contrast microscopy. The option to select or monitor individual cells online with such light microscopy techniques while performing atomic force microscopy (AFM) measurements is therefore extremely beneficial. Here, we report two conceptually different strategies to implement these light microscopy techniques in a fully functional AFM head at the ultimate resolution of the Abbe diffraction limit.