Chip-scale blue light phased array

Abstract

Compact beam steering in the visible spectral range is required for a wide range of emerging applications, such as augmented and virtual reality displays, optical traps for quantum information processing, biological sensing, and stimulation. Optical phased arrays (OPAs) can shape and steer light to enable these applications with no moving parts on a compact chip. However, OPA demonstrations have been mainly limited to the near-infrared spectral range due to the fabrication and material challenges imposed by the shorter wavelengths. Here, we demonstrate the first chip-scale phased array operating at blue wavelengths (488 nm) using a high-confinement silicon nitride platform. We use a sparse aperiodic emitter layout to mitigate fabrication constraints at this short wavelength and achieve wide-angle beam steering over a 50° field of view with a full width at half-maximum beam size of 0.17°. Large-scale integration of this platform paves the way for fully reconfigurable chip-scale three-dimensional volumetric light projection across the entire visible range.

Electrically Driven Reprogrammable Vanadium Dioxide Metasurface Using Binary Control for Broadband Beam Steering

“…When the purely dielectric and purely metallic states have a reasonably high reflectance, the antenna are more suitable for binary control, as will be discussed further below. A similar design has previously been manufactured with a thinner SiO 2 layer; the fabrication protocol can be used for the structure studied herein., , …”

“…LIDAR systems still vastly rely on mechanical control that requires high precision and is slow and expensive. Photonics integrated circuits are being investigated ,, and offer promising improvements, but they still require individual calibration, high power consumption, and are complex structures to fabricate. The transfer of phased arrays from RF/mmW ranges to the optical domain would enable a drastic reduction in cost, size, complexity, reliability, and energy consumption for LIDAR systems and also enable a new generation of two-dimensional (2D) reconfigurable optical elements …”

“…One of the main ways to achieve this is by using the phase shift which occurs in a resonant antenna where light and matter strongly couple. − To tune the resonance, several parameters can be changed, many designs modify a geometric feature to achieve phase control with their response fixed at fabrication. , Some designs are switchable and possess two operating states − but to achieve a fully reconfigurable device with a large number of degrees of freedom, each antenna must be individually controlled post-fabrication . For a given geometry, one can change the material properties using the electro-optic effect, carrier doping, − thermo-optic effect, or phase-change materials like germanium–antimony–tellurium alloys (GST) − or vanadium dioxide (VO 2 ). GST-based resonant metasurfaces have been experimentally tested, but the difficulties of experimentally changing its material have only recently been partially lifted .…”

A Design Approach of Optical Phased Array with Low Side Lobe Level and Wide Angle Steering Range

“…The grating lobes cannot be effectively suppressed by weighting the amplitudes and the phases of the array excitation. A lot of research literatures have proved that the grating lobes can be suppressed by using nonuniform arrays [9][10][11][12]. In [12], a nonuniform OPA with 128 antennas is proposed and fabricated by CMOS (complex metal oxide semiconductor) technology compatible with silicon photonic technology.…”

Flexible Photonic Probes for New-Generation Brain–Computer Interfaces

“…However, the commonly used optogenetic proteins are primarily sensitive to visible light. Recently, a 64 channel OPA working in the blue wavelengths was demonstrated by Lipson, achieving a 50° field of view steering. Meanwhile, they also prepared a reconfigurable optical probe operating at 473 nm for neural stimulation .…”