The following is an abstract for the selected article. A PDF download of the full text of this article is available here. Members may download full texts at no charge. Non-members may be charged a small fee for certain articles.
Two-Photon Excitation in Square and Cylindrical Capillaries
Volume 54, Number 8 (Aug. 2000) Page 1203-1207
Zugel, S.A.; Lytle, F.E.
The loss in sensitivity of two-photon excited fluorescence, when switching from a 1 cm cell format to square and cylindrical capillaries, is described quantitatively. Sensitivities are determined with calibration curves, and beam shapes are computed with optical design software. The decreased sensitivity with square capillary (75 μm i.d.) is shown to be the simple result of a truncated pathlength resulting in a factor of ~ 2 reduction in sensitivity from a 1 cm cell. Cylindrical capillary of the same i.d. is characterized by astigmatism caused by the curved refractive index boundary in addition to the truncation. The astigmatism is determined to be smaller in the thin-walled capillary, allowing for better performance than the thick-walled capillary. In fact, the thin-walled capillary is found to have similar performance to the square capillary.