title: Time-lens based hyperspectral stimulated Raman scattering imaging and quantitative spectral analysis.
abstract: We demonstrate a hyperspectral stimulated Raman scattering (SRS) microscope through spectral-transformed excitation. The 1064 nm Stokes pulse was from a synchronized time-lens source, generated through time-domain phase modulation of a continuous wave (CW) laser. The tunable pump pulse was from linear spectral filtering of a femtosecond laser output with an intra-pulse spectral scanning pulse shaper. By electronically modulating the time-lens source at 2.29 MHz, hyperspectral stimulated Raman loss (SRL) images were obtained on a laser-scanning microscope. Using this microscope, DMSO in aqueous solution with a concentration down to 28 mM could be detected at 2 μs time constant. Hyperspectral SRL images of prostate cancer cells were obtained. Multivariate curve resolution analysis was further applied to decompose the SRL images into concentration maps of CH₂ and CH₃ bonds. This method offers exciting potential in label-free imaging of live cells using fingerprint Raman bands.
authors.affiliation: School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA.
authors.forename: Ke
authors.initials: K
authors.lastname: Wang
authors.forename: Delong
authors.initials: D
authors.lastname: Zhang
authors.forename: Kriti
authors.initials: K
authors.lastname: Charan
authors.forename: Mikhail N
authors.initials: MN
authors.lastname: Slipchenko
authors.forename: Ping
authors.initials: P
authors.lastname: Wang
authors.forename: Chris
authors.initials: C
authors.lastname: Xu
authors.forename: Ji-Xin
authors.initials: JX
authors.lastname: Cheng
mesh_terms: D045744:Cell Line, Tumor; D004121:Dimethyl Sulfoxide; D006801:Humans; D007834:Lasers; D007909:Lenses; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods*; D015999:Multivariate Analysis; D013059:Spectrum Analysis, Raman / Q000295:instrumentation / Q000379:methods*; D013997:Time Factors
chemical_list: D004121:Dimethyl Sulfoxide
keywords: hyperspectral; multivariate curve resolution; nonlinear optical microscopy; pulse shaper; stimulated Raman scattering; time-lens