Fabrication of 5D Fresnel Lenses via Additive Manufacturing.

The consistent developments in additive manufacturing (AM) processes are revolutionizing the fabrication of 3-dimensional (3D) parts. Indeed, 3D printing processes are prompt, parallel, material efficient, and cost-effective, along with their capabilities to introduce added dimensions to the computer-aided design (CAD) models. Notably, 3D Printing is making progressive developments to fabricate optical devices such as regular lenses, contact lenses, waveguides, and more recently, Fresnel lenses. But extended functionalities of these optical devices are also desirable. Therefore, we demonstrate masked stereolithography (MSLA) based fabrication of five-dimensional (5D) Fresnel lenses by incorporating color-change phenomena (4th dimension) using thermochromic powder that changes color in response to external temperature variations (25-36 °C). The holographic diffraction effect (5th dimension) is produced by imprinting a diffraction grating during the printing process. Optical focusing performance for the 5D printed lenses has been evaluated by reporting achievable focal length, with <2 mm average deviation, without postprocessing in 450-650 nm spectral range. However, in the near IR region (850-980 nm), the average deviation was around 11.5 mm. Enhanced optical properties along with surface quality have been reported. Thus, MSLA process can fabricate optical components with promising applications in the fields of sensing and communication.