MEMS-tunable dielectric metasurface lens using thin-film PZT for large displacements at low voltages

Abstract

Tunable focusing is a desired property in a wide range of optical imaging and sensing technologies but has tended to require bulky components that cannot be integrated on-chip and have slow actuation speeds. Recently, integration of metasurfaces into electrostatic micro-electromechanical system (MEMS) architectures has shown potential to overcome these challenges but has offered limited out-of-plane displacement range while requiring large voltages. We demonstrate for the first time, to the best of our knowledge, a movable metasurface lens actuated by integrated thin-film PZT MEMS, which has the advantage of offering large displacements at low voltages. An out-of-plane displacement of a metasurface in the range of 7.2 μ m is demonstrated under a voltage application of 23 V. This is roughly twice the displacement at a quarter of the voltage of state of the art electrostatic out-of-plane actuation of metasurfaces. Using this tunability, we demonstrate a varifocal lens doublet with a focal shift of the order of 250 μ m at the wavelength 1.55 μm. The thin-film PZT MEMS-metasurface is a promising platform for miniaturized varifocal components.

Metasurface‐Programmable Wireless Network‐On‐Chip

“…A further possibility may consist in leveraging piezoelectric diaphragms to mechanically alter the chip package boundaries. [ 95 ]…”

“…A further possibility may consist in leveraging piezoelectric diaphragms to mechanically alter the chip package boundaries. [95] If off-the-shelf components are to be used in the meta-atom design, it is critical that the latter allow one to incorporate the packaged varactor diodes. To that end, the meta-atom size would have to increase relative to that presented in Figure 1f.…”

Universal Active Metasurfaces for Ultimate Wavefront Molding by Manipulating the Reflection Singularities

“…The first relies on addressing the pixel-by-pixel dynamical material response to adapt the device's optical properties via distributed external stimuli. [29,30] The second approach relies on mechanical, electrical, and chemical actuation to directly tune the whole MS. [27,31,[32][33][34] This second approach, however, cannot provide arbitrary wavefront reconfigurability. We, therefore, focus on the first approach, as we are searching for an ideal pixel-by-pixel tunable meta-MS with high efficiency.…”

Broadband Mechanically Tunable Metasurface Reflectivity Modulator in the Visible Spectrum

“…In addition, MEMS actuation methods typically offer low power consumption, fast reconfiguration at MHz rates, and high compatibility with industrial fabrication processes, and have opened up the possibility to create a wide variety of movable and tunable optical structures. 21 A majority of MEMS tunable metasurfaces have been demonstrated in the near infrared and THz for applications in telecommunications or imaging, such as MEMS based tunable flat lenses for varifocal components 22 or tunable THz absorbers. 23 In this work, we make use of the advances in fabrication technologies to achieve MEMS that operate a tunable metasurface in the visible domain.…”