hide
Free keywords:
Colloidal and Molecular Electro-Optics
Abstract:
Measurement of temperature changes in nanoliter volumes is a serious problem, especially if both high precision and nanosecond time resolution are required. Exploitation of the anti-Stokes fluorescence of the laserexcited rhodamine 101 dye offers a solution to the problem. We used a pulsed dye laser (bandwidth 20 ns) for time resolved measurements. The T-jump laser and the pulsed detection laser were aligned inside a 1 µm spot of a liquid sample. A DeltaT = 4 K caused 10% increase in fluorescence intensity. The detection was performed with a variable delay between 10 ns and 100 ms after the heating. We could observe special effects caused by shock-waves produced by the fast thermal expansion of the liquid sample. This new technique of time resolved anti-Stokes fluorescence measurements provides a convenient and precise tool to measure small temperature changes in nano-volumes of liquid samples under many different experimental conditions.
