In a significant breakthrough, researchers at the University of Illinois Urbana-Champaign have made great strides in the development of compact and lightweight optics. By utilizing 3D printing technology and porous silicon, they have successfully created visible wavelength achromats. These high-performance micro-optics achieve exceptional focusing efficiencies while minimizing both volume and thickness, making them ideal for miniaturized applications. The results of this groundbreaking research were recently published in Nature Communications.
Traditionally, compound optics have been used to address the issue of color-blurred imaging caused by multiple wavelengths of light present in white light. However, the required stack of lens elements for achromatic lenses is often too thick, rendering them unsuitable for newer, scaled-down technological platforms such as ultracompact visible wavelength cameras, portable microscopes, and wearable devices.
To overcome this limitation, the research team combined a refractive lens with a flat diffractive lens, resulting in a much thinner lens structure. The bottom lens, known as the diffractive lens, focuses red light closer, while the top lens, the refractive lens, focuses red light further away. By canceling each other out, they achieve a focal point at the same spot.
The Role of 3D Printing and Porous Silicon
To bring their concept to fruition, the researchers developed a novel fabrication process called Subsurface Controllable Refractive Index via Beam Exposure (SCRIBE). This manufacturing method involves 3D printing polymeric structures into a porous silicon host medium that provides mechanical support for the optical components.
In the SCRIIBE process, liquid polymer is inserted into the porous silicon, and an ultrafast laser is used to solidify the liquid polymer, forming the lens structure. This approach eliminates the need for external supports, resulting in a more seamless integration of the diffractive and refractive lens elements. The fabrication process not only minimizes the volume and thickness of the lens but also increases ease and efficiency of production.
The compact and lightweight hybrid achromatic imaging system developed through this research holds immense potential for a wide range of applications. An array of these microlenses can be used to reconstruct larger area images, capturing light-field information, which has been a significant challenge for conventional polymer microlenses lacking achromatic properties. The integration of 3D printing and porous silicon has paved the way for groundbreaking applications such as light-field cameras and light-field displays.
Furthermore, the miniaturized and lightweight nature of these achromatic lenses holds promise for various industries. Their compatibility with ultracompact visible wavelength cameras and portable microscopes opens up exciting possibilities for advancements in medical imaging, surveillance, and scientific research. Additionally, the potential use of these lenses in wearable devices could revolutionize fields such as augmented reality and virtual reality.
The breakthrough achieved by the University of Illinois Urbana-Champaign researchers in the field of compact and lightweight optics marks a significant step towards disruptive technological advancements. By harnessing the power of 3D printing and porous silicon, they have successfully developed high-performance hybrid micro-optics that achieve exceptional focusing efficiencies while significantly reducing volume and thickness. The integration of diffractive and refractive lens elements has been seamlessly achieved, eliminating the need for external supports and simplifying the fabrication process. These achromatic lenses hold immense potential for a wide range of applications, including light-field cameras, light-field displays, ultracompact visible wavelength cameras, portable microscopes, and wearable devices. With further research and development, these advancements may shape the future of optics and revolutionize various industries.