We present a lamellar grating interferometer realized with microelectromechanical system technology. It is used as a time-scanning Fourier-transform spectrometer. The motion is carried out by an electrostatic comb drive actuator fabricated by silicon micromachining, particularly by silicon-on-insulator technology. For the first time to our knowledge, we measure the spectrum of an extended white-light source with a resolution of 1.6 nm at a wavelength of 400 nm and of 5.5 nm at 800 nm. The wavelength accuracy is better than 0.5 nm, and the inspected wavelength range extends from 380 to 1100 nm. The optical path difference maximum is 145 mm. The dimensions of the device are 5 mm 3 5 mm.Spectrometry is widely used in industry and research laboratories. There are many different methods that are used in a variety of fields. In particular, Fourier-transform spectroscopy is a powerful technique for investigating weak sources with high resolution. At present, an extended range of Fourier spectrometers is commercially available. However, high resolution involves an elevated degree of mechanism precision and therefore large size and high cost. Recently, lower-resolution miniature spectrometers have become attractive because of new applications, expanding opportunities in a remarkable variety of disciplines and industries.
Instrumentation for dual-probe scanning near-field optical microscopy Rev. Sci. Instrum. 83, 083709 (2012) Quantitative coherent scattering spectra in apertureless terahertz pulse near-field microscopes Appl. Phys. Lett. 101, 011109 (2012) Pump-probe scanning near field optical microscopy: Sub-wavelength resolution chemical imaging and ultrafast local dynamics Appl. Phys. Lett. 100, 153103 (2012) Background-free imaging of plasmonic structures with cross-polarized apertureless scanning near-field optical microscopy Rev. Sci. Instrum. 83, 033704 (2012)
A large-aperture and large-angle MEMS-based 2D pointing mirror is presented. The device is electromagnetically actuated by a moving-magnet/stationary-coil pair and potentially suited for high power laser beam shaping and beam pointing applications, such as LIDAR. The 4×4 mm2 mirror, the radially symmetric compliant membrane, and the off-the-shelf permanent magnet are manually assembled, with the planar coil kept at a well-defined vertical distance from the permanent magnet by simple alignment pins. The mirror and the compliant membrane structures are separately microfabricated on bulk silicon and SOI wafers, respectively. The hybrid integration of microfabricated and off-the-shelf components enable low-risk/high-yield fabrication, while limiting the throughput. The device features minimum inter-axis cross coupling and good linearity and is highly immune to alignment and assembly imperfections, thanks to the robust actuation principle. All the components including the bi-axial electromagnetic actuator provide a device footprint as small as the top mirror, allowing the design to be used in compact and high-fill-factor mirror arrays. With a drive coil of 400 mA and 5.12 W drive power, the total uniaxial dc rotation exceeds ±16° (optical) for both axes with good decoupling. At maximum measured angle (biaxial 10° (mechanical)), a position stability better than 0.05° over 7 h, and a position repeatability of 0.04° over 5000 switching cycles is reported. Thermally, the simulated mirror temperature increases to 64 K above the heat sink temperature with a thermal in-flux of 1 kW m−2, under absolute vacuum.
A new method to release MEMS chips from a wafer without dicing is presented. It can be applied whenever SO1 wafers are used that are structured from both the device and the handle side using DRIE. This method enables the release of extremely fragile structures without any mechanical impact on the chips. No more dicing residues or debris are created and deposited onto the wafer. The basic idea consists of etching deep surrounding trenches on the device and the handle layer that are displaced by about 20 pm and thus create overlapping areas. For release, the buried silicon dioxide between the overlapping areas is etched away using hydrofluoric acid vapor phase etching.
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