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A new lens capability for three-dimensional (3D) focal control is presented using an optofluidic system consisting ofn × narrayed liquid prisms. Each prism module contains two immiscible liquids in a rectangular cuvette. Using the electrowetting effect, the shape of the fluidic interface can be rapidly adjusted to create its straight profile with the prism’s apex angle. Consequently, an incoming ray is steered at the tilted interface due to the refractive index difference between two liquids. To achieve 3D focal control, individual prisms in the arrayed system are simultaneously modulated, allowing incoming light rays to be spatially manipulated and converged on a focal point located atPfocal(fx,fy,fz) in 3D space. Analytical studies were conducted to precisely predict the prism operation required for 3D focal control. Using three liquid prisms positioned on thex-,y-, and 45°-diagonal axes, we experimentally demonstrated 3D focal tunability of the arrayed optofluidic system, achieving focal tuning along lateral, longitudinal, and axial directions as wide as 0 ≤ fx ≤ 30 mm, 0 ≤ fy ≤ 30 mm, and 500 mm ≤ fz ≤ ∞. This focal tunability of the arrayed system allows for 3D control of the lens’s focusing power, which could not be attained by solid-type optics without the use of bulky and complex mechanical moving components. This innovative lens capability for 3D focal control has potential applications in eye-movement tracking for smart displays, autofocusing of smartphone cameras, or solar tracking for smart photovoltaic systems.
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Effective medium metasurfaces using nanoimprinting of the refractive index: design, performance, and predictive tolerance analysis
Production of flat optics incorporating subwavelength features, particularly at visible frequencies, remains a significant challenge. Here, we establish a framework for the design of effective medium metasurfaces (EMM), relying on nanoimprinting of mesoporous silicon to realize a patterned refractive indexn(x,y) corresponding to an arbitrary transmitted phase profileϕ(x,y). The method is used to design the stamp profile required to produce a Fresnel lens and the theoretical performance of the metalens is examined using the finite-difference time-domain method. Additionally, we demonstrate neural network aided Monte Carlo analysis as a method to model the effects of metasurface fabrications errors on EMM performance and process yield.
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- Award ID(s):
- 2047015
- PAR ID:
- 10494003
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Optical Materials Express
- Volume:
- 14
- Issue:
- 4
- ISSN:
- 2159-3930
- Format(s):
- Medium: X Size: Article No. 847
- Size(s):
- Article No. 847
- Sponsoring Org:
- National Science Foundation
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