microoptics

Microoptics is the field of optical components and systems with features in the micrometer to submillimeter range that are used to shape, direct, or manipulate light. It covers passive elements such as microlenses and diffractive structures as well as active micro-optical devices integrated with electronics or MEMS. Microoptics enables compact, cost-efficient optical subsystems for imaging, sensing, and communications.

Common devices include microlens arrays for image capture and illumination, microprisms and micromirrors for routing light, and diffractive optical elements for beam shaping or chromatic correction. On-chip or edge-coupled waveguides, grating couplers, and metasurface-based flat optics are used to control phase, amplitude, and polarization at small scales.

Fabrication relies on microfabrication techniques such as photolithography on glass or silicon, grayscale lithography, reactive ion etching, LIGA, laser micromachining, nanoimprint lithography, and precision molding for plastics. Material choices include glass, silicon, and polymers like PMMA or COCs. Tolerances are tight, with surface quality and roughness impacting optical performance.

Applications span compact cameras in smartphones and medical endoscopes, projection displays and structured lighting, barcode scanners, optical data storage, and sensing systems for environmental or biomedical use. In telecommunications, microoptics enable fiber-to-chip coupling and compact beam shaping in integrated photonics. Research also explores micro-optical components for LiDAR and spectrometry.

Challenges include alignment precision, optical losses, chromatic aberrations in miniature lenses, and thermal stability. Mass production requires robust, low-cost processes and reliable packaging. The field is moving toward integrated micro-optics, diffractive and metasurface elements to realize flat, lightweight, and versatile optical components.