Steering Light with Dynamic Lenses

A new class of flat, ultra­thin optical devices on a chip was developed by scientists from the Center for Nano­scale Materials at Argonne National Labora­tory and Harvard Univer­sity. The new design uses a micro­scopic electro­mechanical device (MEMS) as a platform. The design imparts dynamic and high-speed control to an optical lens for actively steering light.

Optical micro­scope image of a light­weight, flat lens on a micro-electro­mechanical scanner. Integration of the micro-electro­mechanical devices with advanced flat optical surfaces will help create a new paradigm to manipulate light by combining the strength of high-speed dynamic control and precise spatial mani­pulation of light properties. (Source: Center for Nanoscale Materials, ANL)

The ultra­thin lenses, with their ability to mold and shape light, can poten­tially replace bulky tradi­tional curved lenses. Adding active control to this new class of nano­structures will greatly expand their function in optical technologies and overcome their static nature. An optical meta­surface is a designer interface that packs together multiple materials carefully selected for their ability to control light. The resul­ting nanoscale surface can fold and shape light to create a variety of flat optical components.

The researchers’ proto­type uses a micro-electro­mechanical system (MEMS) to bring active control to the static meta­surface lens. The device, a 2-D scanner micro-mirror, focuses light in a range that is common to many optical applications. When triggered electroni­cally, the MEMS platform steers the angle of the lens along two axes and scans the focal spot in each direction. The team fabri­cated the device using standard computer-chip tech­nology and fused the flat lens onto the MEMS with platinum patches.

This method enables inte­gration of other hybrid structures of varying dimen­sions. The new dynamic meta­surface lens has potential across wider fields, such as MEMS-based micro­scope systems and holo­graphic and projec­tion imaging. The researchers foresee designs with thousands of indi­vidually controlled devices onto a single silicon chip that would lead to an unpre­cedented degree of control and mani­pulation of the optical field. (Source: DOE / ANL)

Reference: T. Roy et al.: Dynamic metasurface lens based on MEMS technology, APL Phot. 3, 021302 (2018); DOI: 10.1063/1.5018865

Link: Nanoscience and Technology Division, Argonne National Laboratory, Lemont, USA

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