Abstract

Two-photon absorption (TPA) has found many applications in two-photon fluorescence microscopy, ^1,2 optical power limiting, and noise reduction. Hence, the determination of the TPA cross section, 8, is important. Sensitive fluorescence-based techniques require fluorescence from the sample and additional information such as the fluorescent quantum yield to extract δ.³ On the other hand, Z-scan methods, ⁴ though free from these constraints, usually do not offer enough sensitivity. Here, we present a direct method to detect weak TPA signal.

© 2002 Optical Society of America