title: Heterodyne detected nonlinear optical imaging in a lock-in free manner.
abstract: We report a compact, cost-effective tuned amplifier for frequency-selective amplification of the modulated signal in heterodyne detected nonlinear optical microscopy. Our method improved the signal to noise ratio by an order of magnitude compared to conventional lock-in detection, as demonstrated through stimulated Raman scattering imaging of live cells and tissues at the speed of 2 μsec/pixel. Application of the tuned amplifier to transient absorption microscopy is also demonstrated. The increased signal to noise ratio allowed epi-detected in vivo imaging of myelin and blood in rat spinal cord with high spatial resolution.
authors.affiliation: Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA.
authors.forename: Mikhail N
authors.initials: MN
authors.lastname: Slipchenko
authors.forename: Robert A
authors.initials: RA
authors.lastname: Oglesbee
authors.forename: Delong
authors.initials: D
authors.lastname: Zhang
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Ji-Xin
authors.initials: JX
authors.lastname: Cheng
mesh_terms: D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D007421:Intestine, Small / Q000166:cytology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008853:Microscopy; D017711:Nonlinear Dynamics; D061848:Optical Imaging / Q000379:methods*; D051381:Rats; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013059:Spectrum Analysis, Raman; D013116:Spinal Cord / Q000166:cytology