Measurement of degenerate two-photon absorption spectra of a series of developed two-photon initiators using a dispersive white light continuum Z-scan

作者：Ajami Aliasghar^*; Husinsky Wolfgang; Tromayer Maximilian; Gruber Peter; Liska Robert; Ovsianikov Aleksandr

来源：Applied Physics Letters, 2017, 111(7): 071901.

DOI：10.1063/1.4989917

To achieve efficient micro- and nanostructuring based on two-photon polymerization (2PP), the development and evaluation of specialized two-photon initiators (2PIs) are essential. Hence, a reliable method to determine the two-photon absorption (2PA) spectra of the synthesized 2PIs used for 2PP structuring is crucial. A technique by which absolute visible-to-near-infrared 2PA spectra of degenerate nature can be determined via performing a single dispersive white-light continuum (WLC) Z-scan has been realized. Using a dispersed white light beam containing 8 fs pulses at wavelengths ranging from 650 nm to 950 nm, the nonlinear transmittance as a function of the sample position can be measured for all spectral components by performing a single scan along the laser beam propagation direction. In this work, the 2PA spectrum of three different 2PIs was determined using this technique. 2PP structuring was also accomplished using the developed 2PIs at different wavelengths. Tuning the wavelength of the laser to match the peak of the 2PA spectra of the developed 2PIs resulted in lower intensity thresholds and facilitated higher structuring speeds. As an example, using M2CMK 2PI for 2PP, the scanning speed can be increased up to 5 folds when the laser wavelength is tuned to 760 nm (i.e., 2PA maximum) instead of the conventionally used 800 nm.

• 出版日期2017-8-14