Generation of mid-infrared vortex beams by 3-D printed polymer phase plates. (December 2022)

• Record Type: Journal Article
• Authors: Zhou, Junchao; Lin, Pao Tai
• Is Part Of: Optics & laser technology. Volume 156(2022)
• Publication Date: 2022-12
• Subjects: Mid-infrared -- Polymer spiral phase plates -- Vortex beam; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2022.108509
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: Demonstrate of Orbital Angular Momentum (OAM) in the mid-Infrared region. Apply mid-Infrared transparent polymers for mid-Infrared applications. Develop high-throughput fabrication methods for mid-Infrared components. Demonstrate high conversion efficiency from Gaussian beam to vortex beam. Abstract: Light carrying vortex beam characteristics were demonstrated in the mid-infrared (mid-IR) region using polymer based spiral phase plates (SPP). The SPP was fabricated through three dimensional (3-D) direct laser writing method, which can construct the optical phase according to the mid-IR wavelength of interest. The fabricated SPP consisted of 32 layers and the layer thickness was precisely adjusted between 100 and 600 nm to create 2π helical phase change. The ideal SPP structure and the gradient optical phase diagram were designed and simulated by the finite-difference time-domain (FDTD) method. Characteristic vortex beam profiles with a ring-shaped pattern and a sharp centric dark spot were experimentally illustrated at a wavelength range of λ = 3.1–3.3 µm. The formation of mid-IR OAM through high throughput 3-D writing technology provides critical integrated components to explore quantum photonics and optical communications.