Multi-functional interface between integrated photonics and free space

TL;DR

This paper presents a versatile, robust interface combining photonic integrated circuits with free-space meta-optics, enabling precise light manipulation and shaping without stringent alignment, demonstrated through various optical functions at 780 nm.

Contribution

It introduces a multi-functional, interchangeable platform that simplifies fabrication and alignment challenges in photonic and free-space optical integration.

Findings

Achieved diffraction-limited spots of ~3 microns with hyperboloid metalens.

Maintained optical fidelity despite 35% input deformation and 20 micron misalignments.

Demonstrated a holographic display with SNR > 10.

Abstract

The combination of photonic integrated circuits and free-space meta-optics has the ability to unclasp technological knots that require advanced light manipulation due their conjoined ability to guide and shape electromagnetic waves. The need for large scale access and component interchangeability is essential for rapid prototyping of optical systems. Such capability represents a functional challenge in terms of fabrication and alignment of compound photonic platform. Here, we report a multi-functional interface that demonstrates the capabilities of a flexible and interchangeable combination of a photonic integrated circuit to a free-space coupling chip with different designs of low-loss meta-optics at a wavelength of 780 nm. We show that robustness and fidelity of the designed optical functions can be achieved without prior precise characterization of the free-space input nor stringent alignment between the photonic integrated chip and the meta-optics chip. A diffraction limited spot of approximately 3 micron for a hyperboloid metalens of numerical aperture 0.15 was achieved despite an input Gaussian elliptical deformation of up to 35% and misalignments of the components of up to 20 micron. A holographic display with a peak signal-to-noise ratio of more than 10 compared to its ground truth is also reported using this platform making this work the first interface to shape photonic integrated modes into free space using different diffractive optical functions.