MEMS micromirrors have proven to be very important optical devices with applications ranging from steerable mirrors for switches and cross-connects to spatial light modulators for correcting optical distortions. Usually beam steering and focusing are done with different MEMS devices and tilt angles in excess of 10 degrees are seldom obtained. Here we describe a single MEMS device that combines tip/tilt, piston mode and varifocal capability into a single, low cost device with very large tilt angles. Our device consists of a 400 micron diameter mirror driven with thermal bimorphs. We have demonstrated deflection angles of ± 40 degrees along both axes, a tunable focal length which varies between -0.48 mm to + 20.5 mm and a piston mode range of 300 microns - four separately controllable degrees of freedom in a single device. Potential applications range from smart lighting to optical switches and devices for telecom systems.

Practical VLC (Visible Light Communication) systems are expected to leverage the lighting infrastructure in order to deliver data to devices in a lighting field. These devices can be static or quasistatic (e.g., laptops or IoT devices); however, it is becoming clear that the preponderance of wireless data consumption is dominated by handheld mobile devices which will exhibit varying physical orientations and 3D dynamics. Because free-space optical and visible light communications are primarily line of sight, transmitter radiation patterns and receiver field of view are very important for predicting the data performance. Given dynamic emission characteristics, there is an opportunity to adapt to the receiver. The caveat of dynamic VLC systems is that the quality and distribution of the resulting illumination must be considered as part of the dual goal of providing high quality lighting. In this paper we investigate the impact of device orientation and mobility on static and then dynamic lighting emission under a multi-cell lighting model. From a source standpoint we consider the performance of beam control through angular control and beam focus for one or more sources in a lighting array. Analysis and simulation demonstrate that dynamic beam and luminaire control can increase the AP coverage range by 12.8X under a 1.67 m ceiling height. Furthermore, the use of multiple sources tracking device orientation and position can mitigate off-angle performance degradation by increasing redundancy in the number of available connections. Our proposed techniques, when applied in concert, successfully mitigate common concerns about the viability of VLC and indoor FSO (Free Space Optical Communication) methods related to signal occlusion and device dynamics.

In this paper, we discuss a design for a MEMS parametric amplifier modulated by the Casimir force. We present the theory for such a device and show that it allows for the implementation of a very sensitive voltage measuring technique, where the amplitude of a high quality factor resonator includes a tenth power dependency on an applied DC voltage. This approach opens up a new and powerful measuring modality, applicable to other measurement types.

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MEMS mirrors are currently used in many applications to steer beams of light. An area of continued research is developing mirrors with varifocal capability that allows the beam to be shaped and focused. In this work, we study the varifocal capability of a 380 µm diameter, thermally actuated MEMS mirror with a ± 40°tip-tilt angle and a radius of curvature between -0.48 mm to 20.5 mm. Light is coupled to the mirror via a single mode optical fiber, similar to an indoor optical wireless communication architecture. The performance of the mirror is characterized with respect to (1) the profile of the reflected beam as the mirror deforms and (2) the mirror's impact when integrated into an optical communication system. We found that the mirror can focus light to a beam with a 0.18°half-angle divergence. Additionally, the ability to change the shape of fiberized light from a wide to narrow beam provides an unmatched level of dynamic control and significantly improves the bit error rate in an optical communication system. J. G. Fujimoto, "Handheld ultrahigh speed swept source optical coherence tomography instrument using a MEMS scanning mirror," Biomed.