Picosecond self-induced thermal lensing from colloidal silver nanodisks

2019-08-09 13:05:35

thermal time relaxation phonon nanodisks

责任者: Maillard, Mathieu;Pileni, Marie-Paule;Link, Stephan;El-Sayed, Mostafa A. 单位: Lab. des Mat. Mesoscopiques/N., Univ. Pierre et Marie Curie, 75005 Paris, France 来源出处: Journal of Physical Chemistry B,2004,108(17):5230-5234 摘要: The optical and nonradiative relaxation dynamics of 5 nm thick silver nanodisks with a 25 nm diameter have been investigated in an organic solvent by continuous wave (cw) and femtosecond pump - probe time-resolved spectroscopies. Several surface plasmon absorption bands are observed due to the disk shape of these particles. In the time-resolved experiments, the time dependence of the bleach resulting from femtosecond pulsed excitation is studied. On the 1-3 ps time scale, a decay resulting from electron - phonon relaxation is observed. On a longer time scale (>20 ps), a rise rather than a further decay of the bleach intensity is observed. This is shown to result from the formation of a thermal lens due to the induced thermal gradients produced from heating the organic solvent by the phonon - phonon relaxation processes of the photoexcited nanodisks. 关键词: Silver;Colloids;Nanostructured materials;Relaxation processes;Continuous wave lasers;Bleaching;Photochemical reactions;Phonons;Synthesis (chemical);Bleach recovery;Thermal lensing;Photoexcited nanodisks;Femtosecond pulses