화학공학소재연구정보센터
Journal of Physical Chemistry B, Vol.111, No.9, 2365-2371, 2007
Application of fluorescence correlation spectroscopy to the measurement of local temperature in solutions under optical trapping condition
Fluorescence correlation spectroscopy (FCS) was applied to the quantitative evaluation of the local heating in small domains < 1 mu m in solutions under the laser trapping condition in the presence of a near-infrared (NIR) laser beam at 1064 nm. On the basis of the translational diffusion coefficient of fluorescent molecules obtained by FCS, the relationship between temperature rise and the incident NIR laser power, Delta T/Delta P, were determined to be 62 +/- 6, 49 +/- 7, and 23 +/- 1 deg K/W in ethylene glycol, ethanol, and water, respectively, while no remarkable temperature increase was observed for deuterated water. The value of Delta T/Delta P linearly increased as a function of alpha/lambda (alpha is the extinction coefficient of solvent at the wavelength and lambda is the thermal conductivity of the medium). The validity and the applicability of the present method for the measurement of the local temperature increase were discussed by comparing the present results with previous ones by other various methods.