Scientists propose a new approach to fluorescence color control using optical tweezers. The scientists’ findings were published in the German international journal Angewandte Chemie.

In a new study, scientists have demonstrated the ability to remotely control the wavelength using only the effect of light pressure. Optical tweezers, a technology for holding and moving microparticles using a laser, helped physicists with this. Its peculiarity is that the electric field of the laser beam acting on the particle is capable of pulling it to the center of the beam, providing optical capture.

One of the big stumbling blocks in the field of photonics is the control of the color or wavelength of light. Researchers have to change the chemical structure of the emitter or the concentration of the solvent – all of which require direct contact, which greatly limited the application of technologies.

“Such conditions make it impossible to quickly change color. It cannot be used as a light source in microscopic spaces or in closed systems. Even in cells,” explains Yasuyuki Tsuboi, professor of chemistry at Osaka City University. A new study solves this problem.

During the experiment, the scientists demonstrated an optical capture method using nanotextured silicon (Si). As the laser intensity increased, the local concentration of perylene-labeled polymer chains also increased. Accordingly, the excimer fluorescence of perylene increased and the monomer fluorescence decreased. This is evidenced by a change in the color of the glow from blue to orange. In this way, the scientists were able to remotely and reversibly control the color of fluorescence to change blue, green, yellow-green, yellow and orange.