Four directional circular optical phased array for uniform two-dimensional beam steering at visible wavelength

Area of Science:

• Photonics and Optical Engineering
• Electromagnetics and Wave Propagation

Background:

• Optical phased arrays (OPAs) are crucial for applications like augmented reality and optical imaging due to their precise beam steering capabilities.
• Realizing OPAs at visible wavelengths presents challenges in achieving continuous 2D beam steering.

Purpose of the Study:

• To present a 64-element, two-dimensional (2D) circular optical phased array (OPA) operating at a visible wavelength (632.5 nm).
• To achieve 2D continuous beam steering with pure phase control at visible wavelengths for the first time.

Main Methods:

• Development of arrowhead antennas to minimize residual energy and preserve far-field pattern integrity.
• Implementation of a four-directional array arrangement to broaden the field of view and improve side lobe suppression ratio (SLSR) uniformity.
• Fabrication and measurement of a 64-element 2D circular OPA.

Main Results:

• Demonstration of 2D continuous beam steering with pure phase control at visible wavelengths.
• Achieved an elevation angle of 9° and a full 360° azimuth steering.
• Maintained a side lobe suppression ratio (SLSR) exceeding 3 dB across different azimuth angles.

Conclusions:

• This work represents a significant advancement in visible-light OPA technology, enabling unprecedented 2D continuous beam steering.
• The proposed arrowhead antennas and four-directional array arrangement offer effective solutions for enhancing OPA performance.
• The developed OPA technology holds promise for next-generation augmented reality, free-space optical communication, and optical imaging systems.