Available Technologies

Background

With two-photon absorption where an electronic excitation process in which a single molecule or cluster absorbs two photons simultaneously to reach an excited state, it is possible to selectively induce photoexcitation only in small regions of high light intensity, as well as to use near-infrared light (700–1300 nm), which has high tissue penetration, to achieve similar transitions. However, conventional two-photon absorption materials have faced challenges, such as a small two-photon absorption cross-section and large molecular size. This has led to issues like reduced light absorption efficiency, limited applicability, and potential impacts on biological systems.

Description and Advantages

Kyoto University researchers have applied molecular design rooted in vibronic coupling density (VCD) theory to develop a two-photon absorption material characterized by a large two-photon absorption cross-section and compact molecular size. Moreover, since this material emits in the near-infrared region, it is expected to improve signal strength in fluorescence observation and imaging, reduce damage to samples by enabling lower light intensities and expand the potential for deep-tissue imaging within biological systems.

➢ Significant enhancement of the two-photon absorption cross-section

　In the NIR region (around 850 nm) suitable for biological applications, the two-photon absorption cross-section of this material has been enhanced from approximately 1000 GM in conventional materials to 5200 GM.

➢ Miniaturization of molecular size

　This material is isotropic and compact in size. Additionally, when the two-photon absorption wavelength falls within the NIR region, which exhibits high tissue penetration, it can be utilized within biological systems.