New Orleans Ernest N. Morial Convention Center, New Orleans, Louisiana
March 13, 2017 @ 8:48am in Room 299
Measurement of two-photon absorption cross section of silicon nanocrystals in colloidal suspension
Brandon J. Furey1, Michael C. Downer1, Dorothy A. Silbaugh1, Adrien C. Guillaussier1, Yixuan Yu2, Brian A. Korgel1
1University of Texas at Austin, 2Lawrence Livermore National Laboratory
Two-photon absorption (2PA) in liquid suspensions of ligand-passivated silicon nanocrystals (ncSi) is difficult to measure directly because of their low absorption cross section and competing nonlinear optical processes at high light intensity. Here we overcome these difficulties by measuring background-free, 2PA-induced photoluminescence (PL) as a function of the intensity of ultrashort 800 nm excitation pulses and then calibrating the response by measuring PL induced by one-photon absorption. Using this indirect method, 2PA cross sections of ncSi with diameters 2.2 and 2.7 nm suspended in toluene were 0.505 ± 0.005 and 2.24 ± 0.02 E-50 cm4 s / photon, respectively. This procedure was validated using rhodamine B in ethanol for which the 2PA cross section was 21.8 ± 0.1 E-50 cm4 s / photon, which agrees with direct measurements.\footnote{A. Nag, D. Goswami, J. Photochem. and Photobio. A: Chem. 206 (2-3), 188 (2009)} The size dependence of 2PA cross sections for ncSi and comparisons with other reference samples will be discussed. Water-dispersible ncSi may be suitable for bio-imaging.\footnote{C.M. Hessel, J. Wei, B. Korgel et al., Chem. Mater. 24 (2), 393 (2012)} This application is demonstrated using 2PA confocal microscopy of ncSi-incubated mouse tissue.
Session A36: Quantum Dots, Quantum Wells, and Metamaterials: Optical Characterization and Applications
8:00 AM–11:00 AM, Monday, March 13, 2017
Room: 299
Sponsoring Units: DCMP DMP
Chair: Brennan Pursley, Naval Research Laboratory
Abstract ID: BAPS.2017.MAR.A36.5
Abstract: A36.00005: Measurement of two-photon absorption cross section of silicon nanocrystals in colloidal suspension*
8:48 AM–9:00 AM
Link to more information: https://meetings.aps.org/Meeting/MAR17/Session/A36.5
Brandon J. Furey 