Unlike conventional optical components, which often present physical obstructions to the miniaturization of optoelectronic devices, the control of light using flat optics has attracted much recent attention due to unique technological opportunities presented by these devices. Optical metasurfaces, which are composed of rationally designed nanostructures, are proposed to replace some of the conventional optical elements given their compact size and more importantly, the ability to produce spatially varying phase change, amplitude modulation and polarization conversion of incident light over subwavelength dimensions. For example, a compact, flat lens with dynamically tunable focal length will be an essential component in advanced reconfigurable optical systems. Although there have been some successful demonstrations of active metalenses recently, they all work in the transmission configuration. Here, we design and realize the first reflection type, tunable lens (i.e., metamirror) operating in the visible regime (670 nm). With a designed hyperboloidal phase profile, the metamirror is fabricated on a substrate driven by external force, so its focal length can be adjusted dynamically. It is shown that the focal length can be continuously adjusted by up to 45% with a 0 to 20% lateral stretching of the substrate, while maintaining diffraction-limited focusing and high focusing efficiency. Our design as a flat optics element has strong potential in widespread applications such as wearable mixed reality electronics, biomedical instruments and integrated optics devices.
*firstname.lastname@example.org Design study for a 16x zoom lens system for visible surveillance camera Anthony Vella*, Heng Li, Yang Zhao, Isaac Trumper, Gustavo A. Gandara-Montano, Di Xu, Daniel K. Nikolov, Changchen Chen, Nicolas S. Brown, Andres Guevara-Torres, Hae Won Jung, Jacob Reimers, Julie Bentley The Institute of Optics, University of Rochester, Wilmot Building, 275 Hutchison Rd, Rochester, NY, USA 14627-0186 ABSTRACT High zoom ratio zoom lenses have extensive applications in broadcasting, cinema, and surveillance. Here, we present a design study on a 16x zoom lens with 4 groups (including two internal moving groups), designed for, but not limited to, a visible spectrum surveillance camera. Fifteen different solutions were discovered with nearly diffraction limited performance, using PNPX or PNNP design forms with the stop located in either the third or fourth group. Some interesting patterns and trends in the summarized results include the following: (a) in designs with such a large zoom ratio, the potential of locating the aperture stop in the front half of the system is limited, with ray height variations through zoom necessitating a very large lens diameter; (b) in many cases, the lens zoom motion has significant freedom to vary due to near zero total power in the middle two groups; and (c) we discuss the trade-offs between zoom configuration, stop location, packaging factors, and zoom group aberration sensitivity.