Dec 14 2017
Majority of the optical systems—such as microscopes, sunglasses, laser machining, LCD screens, microprocessors, and so on—function based on a light filtering technology known as vector polarizers.
This week, optical physicists from Nanjing and Nankai University, China, and the University of Central Florida, United States, have reported the features of their innovative vector polarizer in APL Photonics, published by AIP Publishing. The innovative design is a significant development in polarization technology as it allows flexible filtering of a broad array of light sources and creation of new light states.
Light waves have the ability to oscillate with their backward and forward motion aligned along unique directions, where the nature of the alignment is governed by their polarization. A conventional polarizer, similar to a lens in polarized sunglasses, filters light oscillating along all but one direction, where the filtered light is known as polarized light.
An enormous challenge was how to solve the design and fabrication of vector polarizers to tailor the light beams and satisfy the requirements of various applications, the vector polarizer can significantly improve the generation efficiency of vector light beam and may be conducive to achieving a high-performance vector laser.
Hui-Tian Wang, one of the authors of the study.
Wang’s team accomplished a design with the ability to customize phase, light intensity, and polarization.
Such developments can be applied to enhance a range of different optical systems. For example, in super-resolution microscopy, control over polarization can be applied to accomplish far-field focusing even beyond typical diffraction limitations.
The scientists increased polarizer flexibility and efficacy by adopting an innovative liquid-crystal-based design that is dependent on birefringence, where particular polarizations are filtered depending on their refractive indices. Wang elucidated that they tailored the alignment of liquid crystal molecules by using rigorous photo-alignment methods. The team ascertained the structure of the dichroic dye film inside the thin glass compartment prior to addition of the liquid crystal.
The innovative vector polarizers also present manufacturing benefits.
They are flexibly designed and easily fabricated, and have the advantages of the large-size complex structures and the broadband [light waves] operation, however, the vector polarizer we proposed still needs some improvements. For example, we need to improve its alignment quality, i.e., the quality of generated light beams. We also need to improve the spatial resolution for controlling the orientation of liquid crystal molecules.
Hui-Tian Wang, one of the authors of the study.
Wang is specifically thrilled about the potential of the new vector polarizer to produce new polarized light states, which he hopes to apply to create new applications. For instance, entangled vector photon states can be applied in creating innovative technology for quantum communications.