[5p-A409-1~11] 4.2 Bio-and Medical Photonics

▼ [5p-A409-11] Super-Resolution in Two-Photon Excitation Microscopy via Saturated Excitation

〇Ryosuke Oketani¹, Atsushi Doi², Nicholas Smith³, Yasunori Nawa¹, Satoshi Kawata¹, Katsumasa Fujita¹ (1.Eng., Osaka Univ., 2.Olympus Corp., 3.iFReC, Osaka Univ.)

Keywords:Super resolution, Two-photon microscopy, saturated excitation (SAX)

We developed a technique to improve the spatial resolution of two-photon excitation microscopy in deep tissue imaging by utilizing saturated excitation of fluorescence. The saturation of fluorescence predominantly appears at the center of the excitation focal spot, which is smaller than the diffraction limit. The 4th-order nonlinearity induced by the combination of SAX and two-photon excitation reduces the emission volume of the fluorescence. We also utilized core-ring illumination to accentuate the high spatial frequency components gained by SAX in the fluorescence images, which is useful in practical conditions with a limited signal-to-noise ratio. From the observation of fluorescent beads with a diameter of 100 nm embedded at the depth of 100 µm, we confirmed the spatial resolution was improved in the deep tissue imaging.