Flip-chip distributed MEMS transmission lines (DMTLs) for biosensing applications

Design and characterization of a flip-chip distributed MEMS transmission line (DMTL) are presented. The concept of using this DMTL as a biosensor is then introduced. Radio frequency experiments on the DMTL loaded with biosamples have been conducted using the most accessible materials, namely, deionized water and aqueous solutions of salts. Results show that the reflection coefficient (S11) of the solution-loaded DMTL is very sensitive to the salt concentration of the solution in the low-frequency ranges of 10 MHz-1 GHz and 3-4.5 GHz. At high frequencies, the relative dielectric constant of the biosample can also be quantitatively determined from the impedance of the DMTL

Analysis of microsprings for calculating the force produced by microactuators

We present models of two types of microsprings namely box-spring and zig-zag spring that can be used to measure the force generated by microactuators. The spring constant for both springs is calculated by FEM using ANSYS software. In these models, the effects of short beams that act as connectors in the spring structures are considered and analyzed by changing their width. Also, from the results, we find that the box spring appears more balanced than the zig-zag spring when the force is applied in the single central direction. A series of SDAs with box spring have been fabricated and forces ofthose SDAs have been calculated

MEMS micromirror based light sheet generator for biomedical imaging

Two MEMS micromirrors with resonant or static actuation are used as a MEMS enabled light sheet generator, with light sheet dimensions of 3.5μm by 550μm and offset positioning of 150μm in the focal plane

MEMS-actuated wavelength drop filter based on microsphere whispering gallery modes

MEMS-enabled tuneable optical coupling between optical microsphere resonators and optical fibre waveguides is reported. We describe the design, fabrication and experimental characterization of a MEMS platform, based on electrothermal actuators, which controls the resonator-to-waveguide separation. We compare the simulated and experimental displacements of the actuators in an unloaded and loaded state, where the load is a 1 mm optical spherical resonator. We then demonstrate the proof of concept application of selective wavelength dropping using the MEMS platform by modulating the coupling between the spherical resonator and a tapered optical fibre waveguide

Light-sheet microscopy using MEMS and active optics for 3D image acquisition control

A miniaturized version of a light-sheet microscopy (LSM) system, with 3D imaging enabled through active optical control, is presented. Even though the field of LSM technology has advanced significantly in recent years, it is still not considered an easily available technique. This is mainly due to its cost compared to epifluorescence setups and the requirement for specific sample mounting techniques in most cases, as well as stringent optical alignment and difficulty to reduce motion artifacts when the sample is moved through the light path to create the imaging slices. In our research, we demonstrate a miniaturized version of an LSM that can reduce size and cost, and is able to achieve 3D imaging through control of multiple active optical elements and MEMS micromirrors used in both the illumination and imaging path instead of moving the sample. The laser excitation is controlled and shaped via multiple MEMS elements for 3D beam position control and multilens beam shaping to generate a 2.85 μm wide light-sheet with controllable height of up to 550 μm, and orthogonal positioning over a 200 μm range. Additionally, the focal point of the excitation can be shifted along the laser propagation direction by 200 μm. The orthogonally positioned imaging path incorporates a x20, NA = 0.4 objective and a tunable lens for imaging selected focal planes synchronized with the excitation positioning. The imaging results show sub-micron resolution with a field-of-view of 400 μm x 300 μm. The synchronization of the two active elements allows for fast imaging of different slices of a sample and promises convenient 3D reconstruction and representation of cell tissue

Bio-inspired sound localization sensor with high directional sensitivity

MEMS microphones inspired by Ormia ochracea are constrained by their reliance on the resonant behavior of the system, forcing designers to compromise the goal of high amplification of directional cues to operate across the audio range. Here we present an alternative approach, namely a system optimized for the maximum amplification of directional cues across a narrow bandwidth operating purely as a sound-localization sensor for wide-band noise. Directional sensitivity is enhanced by increasing the coupling strength beyond the 'dual optimization' point, which represents the collocation of a local maximum in directional sensitivity and a local minimum in non-linearity, compensating for the loss of the desirable linearity of the system by restricting the angular range of operation. Intensity gain achieved is 16.3 dB at 10° sound source azimuth with a linear directional sensitivity of 1.6 dB per degree, while linear directional sensitivity in phase difference gain shows a seven fold increase over the 'dual optimization' point of 8 degrees phase difference per degree change in azimuthal angle

Modeling and characterization of a vernier latching MEMS variable optical attenuator

We report on the modeling and testing of a Vernier latched MEMS variable optical attenuator (VOA) which uses chevron electrothermal microactuators to control fiber-to-fiber optical power coupling. The use of microlatches has the advantage of holding the mechanical position of the fiber, and therefore the level of attenuation, with no electrical energy supplied except only to change the attenuation. Results of analytical electro-thermo-mechanical models of the device are obtained and compared with experimental test results, showing a good agreement. A step resolution of 0.5 μm for this multi-state latched device is achieved using a Vernier latch approach. This incremental step size is smaller than previously reported latched microactuators. The VOA demonstrated an attenuation range of over 47 dB and an insertion loss of 1 dB. The wavelength dependent loss across the optical communications C-band is 1.4 dB at 40 dB attenuation and the 10-90% transition time of the unlatched VOA is measured to be 1.7 ms

Single mode fiber variable optical attenuator based on a ferrofluid shutter

We report on the fabrication and characterization of a single-mode fiber variable optical attenuator (VOA) based on a ferrofluid shutter actuated by a magnetic field created by a low voltage electromagnet. We compare the performance of a VOA using oil-based ferrofluid, with one VOA using water-based 12 ferrofluid, and demonstrate broadband optical attenuation of up to 28 dB with polarization dependent 13 loss of 0.85 dB. Our optofluidic VOA has advantages over MEMS-based VOAs such as simple construction and the absence of mechanical moving parts

Transmissive optical fiber magnetic field sensor based on ferrofluids

A compact optical fiber magnetic field sensor is reported which relies on the magnetic field induced displacement of a ferrofluid lying in the gap between two single mode optical fibers (SMFs) that are aligned face to face. The ferrofluid displacement alters the coupling of light from the input optical fiber to the output optical fiber. When the applied magnetic field changes from 0 mT to 10 mT the optical attenuation changes from 0 dB to -28 dB

Q-switched tunable solid-state laser using a MOEMS mirror

Simultaneous wavelength tuning and Q-switching of a Yb:KGW laser using a single, electrothermally actuated MOEMS mirror is reported for the first time. A 15.4 nm tuning range is achieved at 2.06 kHz pulse repetition frequency