Significant Enhancement of Circular Polarization in Light Emission through Controlling Helical Pitches of Semiconductor Nanohelices

Circularly polarized light emission (CPLE) can be potentially applied to three-dimensional displays, information storage, and biometry. However, these applications are practically limited by a low purity of circular polarization, i.e., the small optical dissymmetry factor g(CPLE). Herein, glancing angle deposition (GLAD) is performed to produce inorganic nanohelices (NHs) to generate CPLE with large g(CPLE) values. CdSe NHs emit red CPLE with g(CPLE) = 0.15 at a helical pitch (P) approximate to 570 nm, having a 40-fold amplification of g(CPLE) compared to that at P approximate to 160 nm. Ceria NHs emit ultraviolet-blue CPLE with g(CPLE) approximate to 0.06 at P approximate to 830 nm, with a 10(3)-fold amplification compared to that at P approximate to 110 nm. Both the photoluminescence and scattering among the close-packed NHs complicatedly account for the large g(CPLE) values, as revealed by the numerical simulations. The GLAD-based NH-fabrication platform is devised to generate CPLE with engineerable color and large g(CPLE) = 10(-2)-10(-1), shedding light on the commercialization of CPLE devices.