Long-lifetime measurement and control of local temperature using functional gel-tool containing quantum dot by color analysis of fluorescent spectrum

We developed a novel temperature measurement and control method using temperature dependence of quantum dots (Q-dots). We used hydrogel-tool containing Q-dots for temperature measurement and control. These tools can be manipulated in a solution by optical tweezers. We used image processing to obtain color information for measuring the temperature. We calibrated the temperature using the gel-tool in YCrCb (Y: brightness, Cr: red color difference, Cb: blue color difference) color space. Y and Cr decrease monotonously with increasing temperature, whereas and Cb do not vary monotonically with temperature change. Cr is suitable for long-time temperature measurement because the Cr is robust against brightness fluctuations. This method has a sensitivity of -1.3 %/K and an accuracy of ±0.3 K. Moreover, we also demonstrated temperature control of the local environment using focused laser with temperature monitoring using the gel-tool.