Microlens Array Fabrication for Advanced Optical Systems

Microlens arrays (MLAs) constitute a pivotal class of micro-optical components, comprising closely packed miniature lenses on a common substrate. Their unique ability to manipulate light at micrometre scales underpins innovations in imaging, sensing, display technologies and on-chip optical integration. Fabrication methods have evolved from conventional thermal reflow and photolithography to advanced direct-writing approaches, self-assembly techniques and mould-free processes. These enable precise control over lens curvature, numerical aperture and surface quality, allowing conformal MLAs on flat and curved substrates alike. Recent efforts have targeted scalability, cost-effectiveness and multifunctionality, integrating MLAs with neuromorphic sensors, microfluidics and photonic circuits. Applications span from ultra-compact cameras with compound-eye architectures to high-resolution displays and fluorescence-enhanced sensors. Ongoing challenges include uniformity over large areas, replication on non-planar surfaces and integration with complementary metal-oxide-semiconductor detectors. Progress in femtosecond laser processing, selective wetting and droplet-based lithography promises to overcome these hurdles, offering pathways to mass production of high-performance MLAs for next-generation optical systems.

Research from Nature Portfolio

Recent studies have demonstrated a hemispherical artificial eye integrating a dense microlens array with a neuromorphic perovskite-nanowire retina and tunable liquid-crystal optics. The work exploits bidirectional synaptic photo-responses across wavelength-dependent perovskite nanowire hybrids to achieve filter-free colour vision and in-device preprocessing. By bias-tuning the liquid-crystal element, full-colour reconstruction is realised, while the hemispherical MLA provides wide field-of-view and low aberration. This bioinspired system approaches the adaptive, wide-angle imaging capabilities of natural compound eyes and paves the way for compact, pre-processing cameras in robotics, surveillance and augmented-reality platforms.

Microlens Array Fabrication for Advanced Optical Systems publication trend

The graph below shows the total number of articles in microlens array fabrication for advanced optical systems across all publications each year (not limited to Nature Index journals).

Technical terms

Microlens array: An assembly of miniature lenses arranged in a regular pattern on a single substrate to manipulate light fields with high spatial density.

Numerical aperture (NA): A dimensionless number characterising the light-gathering power and resolving capability of a lens, defined by the sine of the half-angle of the maximum cone of light that can enter or exit the lens.

Femtosecond laser two-photon photopolymerization: A direct-writing technique that uses ultrashort laser pulses to induce localized polymer cross-linking, enabling three-dimensional microstructure fabrication with submicrometre resolution.

Soft lithography: A set of patterning techniques using elastomeric stamps or moulds to transfer micro- and nano-scale features onto substrates, often via replica moulding.

Thermal reflow: A process in which patterned photoresist or polymer features are heated above their glass transition temperature, causing them to reflow into smooth, curved lens-like shapes under surface tension.

References

1. Fabrication of Microlens Array and Its Application: A Review. Chinese Journal of Mechanical Engineering (2018).
2. A neuromorphic bionic eye with filter-free color vision using hemispherical perovskite nanowire array retina. Nature Communications (2023).
3. Mold-free self-assembled scalable microlens arrays with ultrasmooth surface and record-high resolution. Light: Science & Applications (2023).
4. Artificial Compound Eye with Tunable Properties for Enhancement in Fluorescence Imaging and Raman Detection. Advanced Functional Materials (2024).
5. Multifocal microlens arrays using multilayer photolithography.. Optics Express (2020).