Differentiate between left and right particles using the force exerted by light

Scanning electron microscope images show D and L-shaped gold nanoparticles. The interiors depict the 3D models of the nanoparticles. Credit: NINS/IMS

The researchers investigated the polarization dependence of the force exerted by circularly polarized light (CPL) by performing optical trapping of chiral nanoparticles. They found that the left and right CPL exert different optical gradient force strengths on the nanoparticles, and the D and L shape particles are subjected to different gradient force strengths by the CPL. The present results indicate that the separation of materials according to their variability can be achieved by optical power.

Chirality is the property that a structure cannot be superimposed on its inverse image. Spiral materials display the distinctive feature that they respond differently to left and right circularly polarized light. When issue It is irradiated with strong laser light, optical duty on him. It is theoretically expected that the optical force exerted on chiral materials by left and right circularly polarized light will also be different.

The research group at the Institute of Molecular Sciences and three other universities used an experimental optical convolution technique to observe optical-dependent circular polarization. regression The force exerted on chiral gold nanoparticles. The chiral gold nanoparticles have either a D-shaped (right-handed) or L-shaped (left-handed), and the experiment was performed using both.

The optical force exerted on the nanoparticles depends on the penetration of the incident circularly polarized light. Credit: NINS/IMS

Although the optical gradient force acting on chiral nanoparticles has been theoretically predicted, no observation of the force has been reported before. The research group succeeded in observing the gradient-induced optical strength (that is, the difference between the gradient strength by left and right circularly polarized light), by optical trapping of chiral gold nanoparticles.

Spiral materials display the distinctive feature that they respond differently to left and right circularly polarized light (optical activity). The response of a D-shaped molecule to left-circularly polarized light is the same as that of an L-shaped molecule to right-handed circularly-polarized light, and vice versa. Credit: NINS/IMS

The results showed that the optical gradient strength was different for the D- and L-form molecules. The researchers also found, from the dependence of the strength on the wavelength of the light used, that there is a previously unknown effect on the mechanism of charale– Optical powers supported.

Differentiate between left and right particles according to the force exerted by the light

The plots are the experimental data and the dashed line is the theoretical calculation. Red and blue in the plots and the line represent the D- and L-shaped nanoparticles, respectively. The optical gradient strength was different for the D and L shape particles. Credit: NINS/IMS

The current study explained the properties of optical gradient strength dependent on circular polarization on helix mechanics He went Nanoparticles. It demonstrates the possibility of optical force separation of chiral materials, which can be achieved by using locally confined light generated on nanostructures to trap the materials and/or by using the optical force of other mechanisms.

The search was published in science progress.

Chirality-assisted lateral momentum transfer for bidirectional selective separation

more information:
Junsuke Yamanishi et al, The strength of an optical gradient on chiral particles, science progress (2022). DOI: 10.1126 / sciadv.abq2604. www.science.org/doi/10.1126/sciadv.abq2604

the quote: Differentiating Right and Left Particles Using the Force Exerted by Light (2022, September 21), Retrieved September 21, 2022 from

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