Microlens Arrays: Versatile and Efficient

Imagine integrating the power of nature’s compound eyes into a compact optical assembly just 10 mm by 10 mm. With microlens arrays, this is now possible. These arrays are ideal for homogenizing light from line-narrowed excimer lasers or high-power LEDs, delivering high efficiency and non-Gaussian uniformity. Comprising numerous tiny microlenses arranged in one or two-dimensional arrays, they revolutionize light management in various applications.

Design and Composition of Microlens Arrays

Microlens arrays can be produced as separate optical components or incorporated into larger systems. They might be mounted within metal or polymer structures for easy integration. Each array can include thousands to millions of microlenses, arranged in grids, rectangles, or circles. Key parameters such as focal length, transmitted wavefront quality, and size define their performance.

Most microlens arrays are made from UV fused silica, known for its excellent transmission from UV to IR. The fill factor, which depends on the microlenses’ geometry and arrangement, is typically high to prevent zero-order hotspots. These arrays offer a large field of view, low aberration and distortion, infinite depth of field, and high temporal resolution, making them indispensable in various fields.

Design of Microlens Arrays

Advanced Fabrication Techniques

The fabrication of microlens arrays differs significantly from traditional lens manufacturing due to their minute size. Typically, all microlenses in an array are produced in a single step, often using semiconductor processing technologies.

Methods of Fabrication:

1. Photolithography: Utilizes a lens pattern defined by a photolithographic mask.
2. Etching Techniques: Carves the lenses into the substrate.
3. Hot Embossing and Printing: Relies on the surface tension of the liquified substrate to form lenses.
4. Laser Materials Processing: Forms lenses individually using multiple processing beams, offering high versatility but at a higher cost.

Applications of Microlens Arrays

• Light Collection and Efficiency:
  • Enhance efficiency by collecting light that would otherwise fall on non-sensitive sensor areas.
  • Used in digital projectors and photocopiers to focus light effectively.
• Beam Homogenization and Shaping:
  • Used to homogenize and shape beams or collimate the output of fiber arrays.
  • Ideal for welding, drilling, fiber coupling, and laser ablation.
  • Fly’s eye condenser arrays, made of dual-surface micro cylindrical lenses, are perfect for flat-top and line generation, commonly used in fluorescence microscopy, semiconductor instrumentation, and medical laser applications.
• Shack-Hartmann Wavefront Sensor:
  • Measures the wavefront shape of incident light, used in adaptive optics.
  • Essential in telescopes and attenuated laser beams to determine wavefront distortions accurately.
• Light Field Cameras:
  • Integrated into light field cameras between the main lens and light sensor.
  • Allows capturing images without pre-focus; focus is adjusted during post-processing.
• Other Applications:
  • Serve as solar concentrators, focusing sunlight onto solar cells.
  • Utilized in optical switches and modulators within fiber optic communication systems.
  • Employed in AR and VR imaging systems, optical microscopy, and spectroscopy.

Custom Microlens Arrays for Your Needs

Interested in exploring the capabilities of microlens arrays for your optical systems? At Shanghai Optics, we specialize in custom optics designed to meet your specific requirements, including microlens arrays. Contact us today for more information or to schedule an initial consultation.

Contact Shanghai Optics today! We’d be more than happy to discuss your projects and how to best bring them to fruition.