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Measuring two-photon microscopy ultrafast laser pulse duration at the sample plane using time-correlated single-photon counting

Two-photon microscopy (2PM) has revolutionized biomedical imaging by allowing thin optical sectioning in relatively thick biological specimens. Because dispersive microscope components in 2PM, such as objective lens, can alter temporal laser pulse width (typically being broader at the sample plane),...

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Detalles Bibliográficos
Autores principales: Kim, Youngchan, Vogel, Steven S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Society of Photo-Optical Instrumentation Engineers 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6987257/
https://www.ncbi.nlm.nih.gov/pubmed/31994362
http://dx.doi.org/10.1117/1.JBO.25.1.014516
Descripción
Sumario:Two-photon microscopy (2PM) has revolutionized biomedical imaging by allowing thin optical sectioning in relatively thick biological specimens. Because dispersive microscope components in 2PM, such as objective lens, can alter temporal laser pulse width (typically being broader at the sample plane), for accurate measurements of two-photon absorption properties, it is important to characterize pulse duration at the sample plane. We present a simple modification to a two-photon microscope light path that allows for second-harmonic-generation-based interferometric autocorrelation measurements to characterize ultrafast laser pulse duration at the sample plane using time-correlated single-photon counting (TCSPC). We show that TCSPC can be used as a simple and versatile method to estimate the zero time delay step value between two adjacent ultrafast laser pulses for these measurements. To demonstrate the utility of this modification, we measured the Coherent Chameleon-Ultra II Ti:sapphire laser pulse width at the sample plane using a [Formula: see text] air, [Formula: see text] air, or [Formula: see text] water-immersion objective lens. At 950-nm two-photon excitation, the measured pulse width was [Formula: see text] , [Formula: see text] , and [Formula: see text] ([Formula: see text] , [Formula: see text]), respectively.