Second-harmonic-generation microscope with a microlens array scanner

We propose a multifocus scanning technique in second-harmonic-generation (SHG) microscopy in which the SHG detection efficiency and the image acquisition rate are improved by several tens of times compared with typical single-focus scanning techniques. Because of a microlens array scanner, the laser beam of a mode-locked Ti:sapphire laser is split into ~100 beamlets, and the same number of foci are formed in the specimen. Parallel scanning of the foci enables us to observe real-time images of the specimen. The imaging properties and the usefulness of the microscope are demonstrated by SHG images of living HeLa cells and rat cardiac myocytes.