arXiv subjects

Stephen A. Boppart

Publications and source records attributed to Stephen A. Boppart.

3 recordsLinked to original sources

arXiv2023

Pixelation with concentration-encoded effective photons for molecular optical sectioning microscopy

Quality control in molecular optical sectioning microscopy is indispensable for transforming acquired digital images from qualitative descriptions to quantitative data. Although numerous tools, metrics, and phantoms have been developed, accurate quantitative comparisons of data from different microscopy systems with diverse acquisition conditions remains a challenge. Here, we develop a simple tool based on an absolute measurement of bulk fluorophore solutions with related Poisson photon statistics, to overcome this obstacle. Demonstrated in a prototypical multiphoton microscope, our tool unifies the unit of pixelated measurement to enable objective comparison of imaging performance across different modalities, microscopes, components/settings, and molecular targets. The application of this tool in live specimens identifies an attractive methodology for quantitative imaging, which rapidly acquires low signal-to-noise frames with either gentle illumination or low-concentration fluorescence labeling.

physics.optics↗

arXiv2022

Compact simultaneous label-free autofluorescence multi-harmonic (SLAM) microscopy for user-friendly photodamage-monitored imaging

Label-free nonlinear optical microscopy has become a powerful tool for biomedical research. However, the possible photodamage risk hinder further clinical applications. To reduce these adverse effects, we constructed a new platform of simultaneous label-free autofluorescence multiharmonic (SLAM) microscopy, featuring 5-channel multimodal imaging, inline photodamage monitoring, and pulse repetition-rate tuning. By the use of a birefringent photonic crystal fiber for spectral broadening (rather than supercontinuum generation) and a prism compressor for pulse pre-chirping, this system allows users to independently adjust pulse width, repetition rate, and energy, which is useful for optimizing imaging condition towards no/minimal photodamage. Also, it demonstrates label-free multichannel imaging at one excitation pulse per image pixel and thus paves the way for improving the imaging speed by a faster optical scanner.

physics.optics↗

arXiv2004

Interferometric differentiation between resonant Coherent Anti-Stokes Raman Scattering and nonresonant four-wave-mixing processes

A major impediment of using Coherent Anti-Stokes Raman Scattering to identify biological molecules is that the illumination levels required to produce a measurable signal often also produce significant nonresonant background from the medium, especially from water, that is not specific to the resonance being investigated. We present a method of using nonlinear interferometry to measure the temporal shape of the anti-Stokes signal to differentiate which components are resonant and nonresonant. This method is easily adaptable to most existing pulsed CARS illumination methods and should allow for distinguishing resonant CARS when using higher energy pulses. By examining the differences between signals produced by acetone and water, we show that the resonant and nonresonant signals can be clearly differentiated.

physics.optics↗