The researchers investigated the polarization-dependence of the energy of circularly polarized light (CPL) by making optical traps of chiral nanoparticles. They found that the (Power of light to identify what is on the right and left) left and right CPL showed different strengths of the optical gradient energy in the nanoparticles, and the D- and L-type sections were under different gradient strengths from the CPL. The present results suggest that the separation of materials according to their chirality can be accomplished through optical power.
Chirality is a property of this structure that is not possible in its mirror image. Chiral objects exhibit characteristic properties in that they respond differently to left-handed and right-handed light. When a strong laser light is used to scatter an object, optical energy is applied to it. It is expected that the optical power applied to a chiral material (Power of light to identify what is on the right and left) by left and right circular light will also be different.
A research team from the Institute for Molecular Science and three other universities used an optical scanning technique to observe the optical gradient force based on the circularity of chiral gold nanoparticles. Chiral gold nanoparticles with D-shape (right) or L-shape (left), both were used in the experiment.
Although the optical gradient force acting on chiral nanoparticles has been predicted, no observation of this force has been previously reported. The same research was successful in observing the optical energy gradient from chirality (that is, the difference between the energy gradient from left-handed and right-handed light), through the optical trapping of chiral gold nanoparticles.
The results show that the optical gradient power is different for the D-type and L-type. The researchers also found, from the dependence of the power and the wavelength of the light used, that there is an unknown effect on the method of optical power depending chirality. The present study describes the characterization of the optical gradient force dependent on the metal of chiral gold nanoparticles. It shows the possibility of separating chiral material by optical energy, which can be achieved by using light to cover the area created in nanostructures to hold the material and/or by using the optical energy of other systems.
The research has been published in Science Advances.
