Simulation of optical radiation force distribution in interference patterns and necessary conditions for chiral structure formation on dielectrics

Abstract

AbstractA chiral structure is formed by the optical radiation force induced by a circularly polarized light that has spin angular momentum; chiral structures are expected to be used for light control devices and molecular chirality discrimination devices. In this paper, we clarify the relationship between the differences in the distributions of the optical radiation force and the possibility of formation of chiral structures. We first simulate the optical radiation force distribution in the case of a Gaussian beam that successfully forms a chiral structure. Given a vector $${\varvec{r}}$$ r with a centre of the light spot $$\mathrm{O}$$ O and polar coordinates $$R(\left|{\varvec{r}}\right|, \theta )$$ R ( r , θ ) , and an optical radiation force vector $${\varvec{F}}$$ F at $$R$$ R , the angle $${\theta }^{\mathrm{^{\prime}}}=\mathrm{\angle }({\varvec{r}}, {\varvec{F}})$$ θ ′ = ∠ ( r , F ) and $$\left|{\varvec{F}}\right|$$ F must be constant with respect to the declination angle $$\theta$$ θ for a chiral structure to form. These conditions are fulfilled in the case of a 6-beam interference pattern, but not in the case of a 4-beam interference pattern, which is consistent with the result that no chiral structure is formed in the latter case. The equations derived for simulation of optical radiation force distribution can be used for any optical intensity distribution, and will be of great help in the research of any dielectrics deformation.