The skin is heterogeneous and exerts strong scattering and aberration onto excitation light in multiphoton microscopy(MPM).Shifting to longer excitation wavelengths may help reduce skin scattering and aberration,poten...The skin is heterogeneous and exerts strong scattering and aberration onto excitation light in multiphoton microscopy(MPM).Shifting to longer excitation wavelengths may help reduce skin scattering and aberration,potentially enabling larger imaging depths.However,previous demonstrations of skin MPM employ excitation wavelengths only up to the 1700 nm window,leaving an open question as to whether longer excitation wavelengths are suitable for deep-skin MPM.Here,in order to explore the longer-wavelength territory,first,we demonstrate characterization of the broadband transmittance of excised mouse skin,revealing a high transmittance window at 2200nm.Then,we demonstrate third-harmonic generation(THG)imaging in mouse skin in vivo excited at this window.With 9mW optical power on the skin surface operating at 1MHz repetition rate,we can get THG signals of 250m below the skin surface.Comparative THG imaging excited at the 1700nm window shows that as imaging depth increases,THG signals decay even faster than those excited at 2200 nm.Our results thus uncover the 2200 nm window as a new,promising excitation window potential for deep-skin MPM.展开更多
基金supported by National Natural Science Foundation of China (NSFC) (Nos.61775143,61975126 and 62075135)the Science and Technology Innovation Commission of Shenzhen under Nos.JCYJ20190808174819083,JCYJ20190808175201640 and KQTD20150710165601017China Postdoctoral Science Foundation (No.2021M702241).
文摘The skin is heterogeneous and exerts strong scattering and aberration onto excitation light in multiphoton microscopy(MPM).Shifting to longer excitation wavelengths may help reduce skin scattering and aberration,potentially enabling larger imaging depths.However,previous demonstrations of skin MPM employ excitation wavelengths only up to the 1700 nm window,leaving an open question as to whether longer excitation wavelengths are suitable for deep-skin MPM.Here,in order to explore the longer-wavelength territory,first,we demonstrate characterization of the broadband transmittance of excised mouse skin,revealing a high transmittance window at 2200nm.Then,we demonstrate third-harmonic generation(THG)imaging in mouse skin in vivo excited at this window.With 9mW optical power on the skin surface operating at 1MHz repetition rate,we can get THG signals of 250m below the skin surface.Comparative THG imaging excited at the 1700nm window shows that as imaging depth increases,THG signals decay even faster than those excited at 2200 nm.Our results thus uncover the 2200 nm window as a new,promising excitation window potential for deep-skin MPM.
