Parallel readout of a microcantilever array using single magnetic actuator and a single photo detector for concurrent detection is reported. The system includes MEMS cantilever array designed for different resonance frequencies, optical elements for laser beam shaping and focusing, one detector and feedback electronics, and single broadband actuator for parallel excitation. The cantilevers are made using a simple one-mask fabrication process with embedded amplitude gratings at the tips. A line shaped laser beam is used to illuminate the cantilevers. A single readout photodiode is placed at the first order diffraction beam location on the Fourier plane. The amplified photodiode signal is fed back into the magnetic actuation using a preamplifier and a broadband current amplifier. In this paper, we report for the first time parallel monitoring of the thermal resonance peaks of inherently frequency-multiplexed MEMS cantilevers. We demonstrated simultaneous self-sustained oscillations of seven cantilevers by using a single actuator and detector in air environment. The method is suitable for low-cost multiplexed portable biosensors.

This paper introduces an analysis on the absorption enhancement in uncooled infrared pixels using resonant plasmon modes in metal structures, and it reports, for the first time in literature, broad-band absorption enhancement using integrated plasmonic structures in microbolometers for unpolarized long-wave IR detection. Different plasmonic structures are designed and simulated on a stack of layers, namely gold, polyimide, and silicon nitride in order to enhance absorption at the long-wave infrared. The simulated structures are fabricated, and the reflectance measurements are conducted using an FTIR Ellipsometer in the 8-12 μm wavelength range. Finite difference time domain (FDTD) simulations are compared to experimental measurement results. Computational and experimental results show similar spectral reflection trends, verifying broad-band absorption enhancement in the spectral range of interest. Moreover, this paper computationally investigates pixel-wise absorption enhancement by plasmonic structures integrated with microbolometer pixels using the FDTD method. Special attention is given during the design to be able to implement the integrated plasmonic structures with the microbolometers without a need to modify the pre-determined microbolometer process flow. The optimized structure with plasmonic layer absorbs 84 % of the unpolarized radiation in the 8-12 μm spectral range on the average, which is a 22 % increase compared to a reference structure with no plasmonic design. Further improvement may be possible by designing multiply coupled resonant structures. © 2012 SPIE

No abstract

No abstract

No abstract