A phase-object (PO) Z-scan technique, which can conveniently distinguish the transient thermal-lensing effect from the third-order nonlinear refraction, is described. The PO Z-scan trace of the transient thermal-lensing effect shows a valley-peak shape that is very different from the single-valley (peak) shape of the pure negative (positive) third-order nonlinearity. The nonlinear refraction of the C70/toluene solution is investigated by using the PO Z scan with 8 ns pulses at 532 nm wavelength as a test.
© 2009 Optical Society of America
Original Manuscript: August 27, 2008
Revised Manuscript: November 7, 2008
Manuscript Accepted: November 25, 2008
Published: January 13, 2009
Junyi Yang and Yinglin Song, "Direct observation of the transient thermal-lensing effect using the phase-object Z-scan technique," Opt. Lett. 34, 157-159 (2009)