Micro-optical design of a three-dimensional microlens scanner for vertically integrated micro-opto-electro-mechanical systems

Abstract

This paper presents the optical design of a miniature 3D scanning system, which is fully compatible with the vertical integration technology of micro-opto-electro-mechanical systems (MOEMS). The constraints related to this integration strategy are considered, resulting in a simple three-element micro-optical setup based on an afocal scanning microlens doublet and a focusing microlens, which is tolerant to axial position inaccuracy. The 3D scanning is achieved by axial and lateral displacement of microlenses of the scanning doublet, realized by micro-electro-mechanical systems microactuators (the transmission scanning approach). Optical scanning performance of the system is determined analytically by use of the extended ray transfer matrix method, leading to two different optical configurations, relying either on a ball lens or plano-convex microlenses. The presented system is aimed to be a core component of miniature MOEMS-based optical devices, which require a 3D optical scanning function, e.g., miniature imaging systems (confocal or optical coherence microscopes) or optical tweezers.

MEMS-tunable dielectric metasurface lens

“…In addition, we show that such devices can be combined with the recently demonstrated monolithic metasurface optical systems design [50] to develop compact focus-scanning objectives with corrected monochromatic aberrations over a large field of view. It is worth noting that MOEMS devices with the ability to axially scan the focus have previously been demonstrated based on integration of refractive and Fresnel microlenses with axially moving frames [6][7][8]55]. However, in these devices the focal point is scanned by the same distance that the lens is moved, and the effective focal length (or equivalently the optical power) is not actually tuned.…”

“…They can also be integrated with a third metasurface to make compact microscopes (∼1 mm thick) with a large corrected field of view (∼500 µm or 40 degrees) and fast axial scanning for 3D imaging. This paves the way towards MEMS-integrated metasurfaces as a platform for tunable and reconfigurable optics.been developed to make such devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18]. Deformable solid and liquid-filled lenses with mechanical [1] , electro-mechanical [2,12], electrowetting [9, 10], and thermal [11] tuning mechanisms have been demonstrated.…”

Technological Platform for Vertical Multi-Wafer Integration of Microscanners and Micro-Optical Components

“…Figure 2b shows the optical design of 3D microscanner, presenting strong correspondence with the stacking architecture of Figure 2a [13]. The equivalent optical system is composed of three blocks: a collimation block, a scanning block, and a focusing block.…”

“…The scanning performance [13] mainly depends on the ratio f 3 / f 2 , where f 2 represents the focal length of the scanning lens, while f 3 is the focal length of the focusing lens. Thus, to amplify the scan amplitude f 3 should be selected higher than f 2 .…”

MEMS-tunable dielectric metasurface lens

“…Compact lenses with tunable focal/imaging distance have many applications, and therefore several methods have been developed to make such devices [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] . Deformable solid and liquid-filled lenses with mechanical 1 , electromechanical 2,12 , electrowetting 9,10 , and thermal 11 tuning mechanisms have been demonstrated.…”