Open AccessUsing pulse transit delay in Z-scan to discriminate between excited-state absorption and other nonlinear processes in ZnO nanocones
Author(s) -
Matthew P. Shortell,
Esa Jaatinen,
Jin Chang,
Eric R. Waclawik
Publication year - 2014
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.22.006222
Subject(s) - optics , nanosecond , absorption (acoustics) , materials science , ultrafast laser spectroscopy , pulse (music) , two photon absorption , excited state , nonlinear system , detector , ultrashort pulse , nonlinear optics , laser , atomic physics , physics , quantum mechanics
We report a new approach that uses the single beam Z-scan technique, to discriminate between excited state absorption (ESA) and two and three photon nonlinear absorption. By measuring the apparent delay or advance of the pulse in reaching the detector, the nonlinear absorption can be unambiguously identified as either instantaneous or transient. The simple method does not require a large range of input fluences or sophisticated pulse-probe experimental apparatus. The technique is easily extended to any absorption process dependent on pulse width and to nonlinear refraction measurements. We demonstrate in particular, that the large nonlinear absorption in ZnO nanocones when exposed to nanosecond 532 nm pulses, is due mostly to ESA, not pure two-photon absorption.