Spherical aberration free liquid-filled tunable lens with variable thickness membrane.

Area of Science:

• Optics and Photonics
• Materials Science
• Mechanical Engineering

Background:

• Conventional tunable lenses often suffer from aberrations, limiting their performance over extended focal length ranges.
• Achieving diffraction-limited performance in tunable optical elements requires precise control over optical surface deformation.
• Spherical aberration is a key challenge in lens design, particularly for systems requiring variable focal lengths.

Purpose of the Study:

• To present an iterative design methodology for liquid-tunable aspherical lenses.
• To engineer elastomer lenses with variable thickness profiles for ideal aspheric deformation under pressure.
• To demonstrate significantly reduced spherical aberration compared to conventional tunable lenses.

Main Methods:

• Utilizing large-deflection thin plate theory for initial meniscus thickness profile calculation.
• Employing iterative optimization through coupled finite element analysis and ray-tracing simulations.
• Analyzing potential fabrication errors and their impact on optical performance.

Main Results:

• Designed a 3 mm clear aperture tunable aspherical lens with an 8 mm optimum focal length.
• Numerically demonstrated improved optical performance over a 6 mm to 12 mm focal length range.
• Achieved better than λ/4 RMS surface error for 10% focal length tuning (7.7 mm to 8.5 mm) using 80% of the clear aperture.

Conclusions:

• The iterative design method enables the creation of high-performance liquid-tunable aspherical lenses.
• The proposed lenses offer superior aberration control and diffraction-limited performance over a wide tuning range.
• The design accounts for practical fabrication challenges, paving the way for real-world implementation.