Experimental determination of single CdSe nanowire absorption cross sections through photothermal imaging.

摘要: Absorption cross sections (σabs) of single branched CdSe nanowires (NWs) have been measured by photothermal heterodyne imaging (PHI). Specifically, PHI signals from isolated gold nanoparticles (NPs) with known were compared to those individual NWs excited at 532 nm. This allowed us determine average NW absorption nm σabs = (3.17 ± 0.44) × 10−11 cm2/μm (standard error reported). agrees well a theoretical value obtained using classical electromagnetic analysis (σabs 5.00 cm2/μm) and also prior ensemble estimates. Furthermore, exhibit significant polarization sensitivities consistent excitation anisotropy measurements. has enabled additional estimates the section parallel (σabs∥) perpendicular (σabs⊥) growth axis, as corresponding (ρabs). Resulting values σabs∥ (5.6 1.1) cm2/μm, σabs⊥ (1.26 0.21) ...