1. Signal degradation in multiple-scattering medium: implication for single focus vs multifoci two-photon microscopy
- Author
-
Karsten Bahlmann, Peter T. C. So, Christof Buehler, and Ki Hean Kim
- Subjects
Physics ,Point spread function ,Photomultiplier ,Optics ,Two-photon excitation microscopy ,business.industry ,Scattering ,Detector ,Charge-coupled device ,business ,Focus (optics) ,Signal - Abstract
High-speed two-photon imaging based on multi-foci excitation requires the use of spatially resolved detectors, such as charge coupled device (CCD) cameras, instead of single channel photomultiplier tube (PMT). The performance of systems based on both a PMT and a CCD in turbid medium was evaluated by measuring the image point spread function (PSF) and the image contrast as a function of depth and scattering coefficient with single point scanning. We found no significant change in the full-width at half maximum of the point spread function (PSF) for depth up to 100 μm. However, the CCD lost contrast significantly faster as a function of depth and increase scattering. This discrepancy is resolved by measuring a low amplitude but broad tail in the PSF distribution. The tail of the PSF distribution can be up to 200 μm in diameter. We further evaluate scattering effects in the imaging of GFP neurons in a mouse brain slice.
- Published
- 2004
- Full Text
- View/download PDF