On-chip monolithic wide-angle field-of-view metalens based on quadratic phase profile

Abstract

With the rapid development of integrated optics, bulky and curved traditional lenses cannot meet the requirements of on-chip optical systems. Alternatively, the metalenses based on the artificial subwavelength structure possess ultra-thin and lightweight characteristics, providing a potential candidate for on-chip optical systems. Nonetheless, most metalenses have a limited field-of-view (FOV) due to the prevalence of severe off-axis aberrations. In this work, we propose and design an on-chip metalens with wide FOV based on the quadratic phase. The metalens modulates the phase of the incident light with different lengths of gold nano-bands placed on the silicon-on-insulator substrate; thus, the quadratic distribution of the phase of the output light can be achieved by shifting the lengths of gold nano-bands and the output light is focused. The metalens can be focused on a large angle (∼120°, ranging from −60° to +60°). Furthermore, the metallic strips in the metalens are very thin with a thickness of 50 nm, which can be easily integrated into a chip. The monolithic metalens of broad FOV and ultrathin thickness will have great potential for applications in areas of sensing, imaging, and on-chip information processing.

Optical metalenses: fundamentals, dispersion manipulation, and applications

“…To tackle this problem, several innovative strategies have been proposed in recent years. As will be discussed below, aplanatic metalenses [80], metalens doublets [81][82][83][84][85], aperture-stop-metalenses [86][87][88][89][90], and quadratic phase [91][92][93][94][95] metalenses were adopted to alleviate the aberrations.…”

Bandwidth bounds for wide-field-of-view dispersion-engineered achromatic metalenses

“…Consequently, this places a theoretical upper bound on the bandwidth of the dispersion-engineered metalens, regardless of the chosen meta-atom library. In this paper, we generalize the bandwidth bounds to wide field-of-view (FOV) [22][23][24][25][26][27] achromatic metalenses. In particular, we show that the maximum achievable bandwidth for dispersion-engineered metalenses decreases not only with an increase in numerical aperture (NA) [19], but also with an increase in the FOV.…”

Bandwidth bounds for wide-field-of-view dispersion-engineered achromatic metalenses

“…Consequently, this places a theoretical upper bound on the bandwidth of the dispersion-engineered metalens, regardless of the chosen meta-atom library. In this paper, we generalize the bandwidth bounds to wide field-of-view (FOV) [22][23][24][25][26][27] achromatic metalenses. In particular, we show that the maximum achievable bandwidth for dispersionengineered metalenses decreases not only with an increase in numerical aperture (NA) [19], but also with an increase in the FOV.…”