Tubular astigmatism-tunable fluidic lens

Area of Science:

• Optics and Photonics
• Materials Science
• Microfluidics

Background:

• Liquid lenses offer tunable optical properties.
• Controlling astigmatism independently is challenging.
• Electrowetting-on-dielectrics (EWOD) provides a method for liquid lens actuation.

Purpose of the Study:

• To demonstrate a new method for fabricating tunable three-dimensional (3D) liquid lenses.
• To achieve independent tuning of focal length and astigmatism.
• To enable precise astigmatism control in arbitrary directions with minimal crosstalk.

Main Methods:

• Fabrication of 3D liquid lenses using rolled planar polyimide foils with structured electrodes.
• Actuation of the liquid lens via electrowetting-on-dielectrics (EWOD).
• Optical and fluidic simulations for lens design optimization.
• Experimental verification using a Shack-Hartmann wavefront sensor to measure Zernike coefficients.

Main Results:

• Demonstrated independent tuning of astigmatism in arbitrary directions with low crosstalk.
• Achieved a 5 mm tuning range for back focal length.
• Tuned 0° and 45° astigmatism by 3 μm using voltages up to 50 Vrms.
• Observed minimal crosstalk with other optical aberrations.

Conclusions:

• The developed fabrication technique enables high-resolution patterning of complex electrodes for precise liquid lens control.
• The EWOD actuation method provides effective and independent control over astigmatism.
• This technology offers a novel solution for astigmatism correction in optical imaging systems.