## Abstract

We report on a novel method designed for measuring two-photon action cross sections spectra in a single shot without tuning the excitation wavelength. Our technique is based on (i) using a nonlinear photonic crystal fiber to broaden the spectrum of the femtosecond excitation pulses and (ii) exploiting angular dispersion to focus different wavelengths to different lateral positions. As a result, two-photon fluorescence signal at different excitation wavelengths can be obtained simultaneously. As a proof of principle, the relative two-photon action cross sections of rhodamine green and DiI-C_{18} are measured over 740–860 nm range using fluorescein as a reference. Our results are in good agreement with that obtained using conventional tunable mode-locked laser.

© 2006 Optical Society of America

Full Article |

PDF Article
### Equations (4)

Equations on this page are rendered with MathJax. Learn more.

(1)
$$<F(t)>=\frac{1}{2}\varphi \eta C\sigma <{I}^{2}(t)>{\int}_{V}dV{S}^{2}(\mathbf{r})\approx \frac{1}{2}g\varphi \eta C\sigma \frac{8n<{P\left(t\right)>}^{2}}{\pi \lambda}$$
(2)
$$\frac{<{F}_{U}\left(t\right)>}{<{F}_{R}\left(t\right)>}=\left(\frac{{\varphi}_{U}}{{\varphi}_{R}}\right)\left(\frac{{C}_{U}}{{C}_{R}}\right)\left(\frac{{n}_{U}}{{n}_{R}}\right)\left(\frac{{\eta}_{U}{\sigma}_{U}}{{\eta}_{R}{\sigma}_{R}}\right)=\left(\frac{{f}_{U}}{{f}_{R}}\times \frac{{d}_{U}}{{d}_{R}}\right)\left(\frac{{C}_{U}}{{C}_{R}}\right)\left(\frac{{n}_{U}}{{n}_{R}}\right)\left(\frac{{\eta}_{U}{\sigma}_{U}}{{\eta}_{R}{\sigma}_{R}}\right)$$
(3)
$${\sigma}_{\mathit{TPE}}^{U}={\eta}_{U}{\sigma}_{U}=\left(\frac{<{F}_{U}\left(t\right)>}{<{F}_{R}\left(t\right)>}\right)\left(\frac{{f}_{R}}{{f}_{U}}\times \frac{{d}_{R}}{{d}_{U}}\right)\left(\frac{{C}_{R}}{{C}_{U}}\right){\sigma}_{\mathit{TPE}}^{R}$$
(4)
$${\sigma}_{\mathit{TPE}}^{U}=\left(\frac{<{F}_{U}\left(t\right)>}{<{F}_{R}\left(t\right)>}\right)\left(\frac{{C}_{R}}{{C}_{U}}\right){\sigma}_{\mathit{TPE}}^{R}$$