Nanopositioning MEMS stage for high speed positioning of metamaterials lenses for use in high resolution optical imaging

High resolution and high throughput imaging are typically mutually exclusive. While there is a wide range of techniques to image features beyond the diffraction limit of light, they all have their own benefits and drawbacks, but they are often very slow compared to optical systems. As such, extending the performance of optical microscopes remains. Examples of high resolution optical concepts are metamaterials nano-antennas, superoscillatory lenses and hyperlenses. These concepts require precise and high speed positioning of the optical element at lens-to-sample separations measured in tens of nanometers. We present a design and process for a MEMS nanopositioning stage capable of sub-nm positioning of a metamaterials optical lens with very high bandwidth. Laser vibrometer measurements on the first batch of fully fabricated devices showed that the first eigenfrequency is at 500±25 kHz, somewhat below the 660 kHz obtained by FEM simulations. Due to squeeze film damping, the quality factor is relatively low (approximately 2-2.5), which is advantageous for reaching high positioning bandwidth when the device is used in a near-field optical imaging microscope.

I. Introduction

When comparing microscopes, the foremost figure of merit is the resolution with which an image can be made. This is fueled by the desire to detect ever-smaller features. This has led to a long chain of developments in search of better techniques and instrumentation, which as of today is relevant as ever [1].