Energy transfer coupling of two-photon absorption and reverse saturable absorption for enhanced optical power limiting

Abstract

We introduce a new approach to enhancing the optical power-limiting function at near-IR wavelength $\left(\sim 800 \mathrm{nm}\right)$ by coupling effective two-photon absorption in one molecule with excited-state absorption in another molecule. We experimentally demonstrate this approach by using a strong two-photon absorbing dye, AF-380, and a strong reverse saturable absorber, ${\mathrm{C}}_{60}$. A nanosecond time-resolved experiment is used to show that energy transfer from AF-380 to ${\mathrm{C}}_{60}$ generates triplet excitation in ${\mathrm{C}}_{60}$ that further absorbs the pump beam to enhance the power-limiting function.