title: Stimulated Raman scattering microscope with shot noise limited sensitivity using subharmonically synchronized laser pulses.
abstract: We propose and demonstrate the use of subharmonically synchronized laser pulses for low-noise lock-in detection in stimulated Raman scattering (SRS) microscopy. In the experiment, Yb-fiber laser pulses at a repetition rate of 38 MHz are successfully synchronized to Ti:sapphire laser pulses at a repetition rate of 76 MHz with a jitter of <8 fs by a two-photon detector and an intra-cavity electro-optic modulator. By using these pulses, high-frequency lock-in detection of SRS signal is accomplished without high-speed optical modulation. The noise level of the lock-in signal is found to be higher than the shot noise limit only by 1.6 dB. We also demonstrate high-contrast, 3D imaging of unlabeled living cells.
authors.affiliation: Department of Material and Life Science, Graduate School of Engineering, Osaka University, Suita, Osaka, Japan. ozeki@mls.eng.osaka-u.ac.jp
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Ozeki
authors.forename: Yuma
authors.initials: Y
authors.lastname: Kitagawa
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Sumimura
authors.forename: Norihiko
authors.initials: N
authors.lastname: Nishizawa
authors.forename: Wataru
authors.initials: W
authors.lastname: Umemura
authors.forename: Shin'ichiro
authors.initials: S
authors.lastname: Kajiyama
authors.forename: Kiichi
authors.initials: K
authors.lastname: Fukui
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Itoh
mesh_terms: D016477:Artifacts; D002467:Cell Nucleus / Q000648:ultrastructure; D002473:Cell Wall / Q000648:ultrastructure; D004867:Equipment Design; D018613:Microscopy, Confocal / Q000295:instrumentation* / Q000379:methods*; D008863:Microspheres; D008928:Mitochondria / Q000648:ultrastructure; D008962:Models, Theoretical; D011137:Polystyrenes; D013059:Spectrum Analysis, Raman / Q000295:instrumentation* / Q000379:methods*; D014026:Nicotiana / Q000166:cytology; D014617:Vacuoles / Q000648:ultrastructure
chemical_list: D011137:Polystyrenes