Fabrication of 5D Fresnel Lenses via Additive Manufacturing

Abstract

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.

UV polymerization fabrication method for polymer composite based optical fiber sensors

“…The tip sensors were colorful (blue and red) at 25 °C and turned transparent for unicolor powder at 35 °C. However, the dual color tip sensor was orange at 25 °C and turned yellow at 31 °C 6 , 26 , 61 . The transmission spectra of pigmented fiber tip sensors were recorded with respect to wavelength for each degree variation of DI water temperature.…”

“…The spectrometer detects targets at spectral regions restricted to visible and near-infrared (VNIR) regimes 59 . The crystallinity of utilized thermochromic powders and any second phase formation during the printing process were confirmed by X-ray diffraction (XRD) analysis using D2 PHASE diffractometer (Bruker, Germany) 6 , 26 , 44 . The XRD experiments were conducted in 5–60° two theta range, with 2.49°/min scan speed and 0.02° incremental step size.…”

“…Before starting temperature measurements, sensors were immersed in DI water for at least 3 h to ensure complete swelling of the developed sensors. The temperature measurements were carried out in hot DI water to confirm homogenized heat distribution in the sensor 6 , 26 , and an attached thermometer monitored the water temperature. The starting temperature of pigmented sensors was 25 °C and was gradually increased by 1 °C to 35 °C and 31 °C for unicolor and dual color powders, respectively.…”

Photopolymerized 3D Printing Materials for Optical Elements

“…Although the laminar structure could be seen after printing, the material is very sensitive to both temperature and strain and has great potential for application in sensing. In addition, the team prepared 5D Fresnel lenses by changing the resin composition and ratios, and the lenses obtained had a complete surface morphology, although the effect of the pixel dots could be seen [ 122 ] (Figure 3b (iii). Based on the examples provided above, it can be inferred that the production of micro‐optical elements using photopolymerization resins with HEMA configurations tends to have a limited impact on the final material properties.…”

“…[115,116] Currently, there is a wide array of photopolymerizable organic materials available for commercial use. Researchers have the flexibility to choose from materials such as 1,6-hexanediol diacrylate (HDDA), [117][118][119][120] 2hydroxyethyl methacrylate (HEMA), [121][122][123][124][125] Bovine serum albumin (BSA) [126,127] and other chemicals, such as pentaerythritol triacrylate (PETA) [128,129] to formulate photopolymerization resins and hydrogels tailored to their specific research needs. Mature commercial photoresists, including the SU-8 series, [130][131][132][133] IP series, [134][135][136][137][138][139] and Opticlear series, [140,13,[141][142][143][144] offer researchers faster and more stable options for organic photopolymerizable materials.…”