Photothermal Lens Detection of Gold Nanoparticles: Theory and Experiments
| Autor: | Vladimir P. Zharov, Anton V. Brusnichkin, Mikhail A. Proskurnin, Dmitry A. Nedosekin |
|---|---|
| Rok vydání: | 2007 |
| Předmět: |
Diagnostic Imaging
Materials science Photochemistry Metal Nanoparticles Physics::Optics Nanoparticle 01 natural sciences law.invention 010309 optics Optics law 0103 physical sciences Laser power scaling Absorption (electromagnetic radiation) Instrumentation Spectroscopy Lenses business.industry Lasers 010401 analytical chemistry Temperature Models Theoretical Photothermal therapy 0104 chemical sciences Lens (optics) Colloidal gold Attenuation coefficient Gold business Refractive index |
| Zdroj: | Applied Spectroscopy. 61:1191-1201 |
| ISSN: | 1943-3530 0003-7028 |
| DOI: | 10.1366/000370207782597175 |
| Popis: | An approach for mode-mismatched two-beam (pump–probe) photothermal lens detection of multipoint light-absorbing targets in solution (e.g., gold nanoparticles) is developed for continuous-wave intensity-modulated laser-excitation mode. A description of the blooming of the thermooptical element (thermal lens) upon absorption of the excitation laser radiation is based on the summation of individual thermal waves from multiple heat sources. This description makes it possible to estimate the irregularities of the temperature (and, thus, the refractive index) profile for a discrete number of nanoparticles in the irradiated area and a change in the concentration and particle size parameters. Experimental results are in good agreement with theoretical dependences of the photothermal signal on nanoparticle size and concentration and excitation laser power. Calibration plots for particles from 2 to 250 nm show long linear ranges, limits of detection of gold nanoparticles at the level of hundreds of nanoparticles with the current setup, and the photothermallens sensitivity coefficient increases as a cubic function of particle size. Further improvements are discussed, including increasing the sensitivity thresholds up to one nanoparticle in the detected volume. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|