Liquid crystal Pancharatnam-Berry phase lens with spatially separated focuses

ABSTRACT

In this paper, we proposed and fabricated a liquid crystal (LC) lens with spatially separated focuses via liquid crystal photoalignment technology. The novel lens is an integration of the polarisation grating and conventional LC lens. The two focuses of that new lens, one of which is real while the other is virtual, can be spatially separated. When combined with normal convex lens and illuminated by a linearly polarised beam, the two emergent light beams become all convergent and the two focuses are separated in three-dimension space. Moreover, the focal lengths of the lens system can be artificially controlled by adjusting the distance between our new lens and the conventional lens. Our results achieve the potential of LC lens’ application in imaging devices such as multifocal cameras, bifocal eyeglasses and so on.

GRAPHICAL ABSTRACT

KEYWORDS:

• Liquid crystal
• Pancharatnam-Berry phase
• lens

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work is supported by the National Natural Science Foundation of China [61605046, 11574079], Natural Science Foundation of Hunan Province [2018JJ3069] and the Fundamental Research Funds for the Central Universities. This work is also supported by the State Key Laboratory of applied optics.