As photonics moves from the single-device level toward large-scale, integrated, and complex systems on a chip, monitoring, control, and stabilization of the components become critical. We need to monitor a circuit non-invasively and apply a simple, fast, and robust feedback control. Here, we show non-invasive monitoring and feedback control of high-quality-factor silicon (Si) photonic resonators assisted by a transparent detector that is directly integrated inside the cavity. Control operations are entirely managed by a CMOS microelectronic circuit that is bridged to the Si photonic chip and hosts many parallel electronic readout channels. Advanced functionalities, such as wavelength tuning, locking, labeling, and swapping, are demonstrated. The non-invasive nature of the transparent monitor and the scalability of the CMOS readout system offer a viable solution for the control of arbitrarily reconfigurable photonic integrated circuits aggregating many components on a single chip.
The first integrated CMOS monolithic sensor system for on-chip capacitive detection of micrometric airborne particulate matter (PM) is presented. The chip is based on a 32 channel lock-in architecture allowing a dust collection area of 1.15 mm2 where interdigitated differential microelectrodes, fabricated with the top metal and directly exposed to air, allow single particle sensitivity. The preamplifier input capacitance is significantly minimized thanks to the electrode-amplifier proximity and proper partitioning of the sensing area, in order to reduce the noise. Each channel comprises a charge preamplifier with adjustable high-pass filtering for flicker noise shaping, square-wave mixer, gm-C tunable low-pass filter (40-750 Hz), and a 6 bit digital network for automatic compensation of electrodes mismatching with a granularity of 150 aF. Thanks to the capacitive noise of only 65 zF rms with 25 ms temporal resolution, deposition events of single mineral talc particles were recorded down to 1μm diameter with a signal-to-noise ratio of 18dB. This chip paves the way to pervasive mapping of both indoor and outdoor PM in the 1-30 μm range
We present a high-speed electrical detection scheme based on a custom-designed CMOS amplifier which allows the analysis of DNA translocation in glass nanopipettes on a microsecond timescale. Translocation of different DNA lengths in KCl electrolyte provides a scaling factor of the DNA translocation time equal to p = 1.22, which is different from values observed previously with nanopipettes in LiCl electrolyte or with nanopores. Based on a theoretical model involving electrophoresis, hydrodynamics and surface friction, we show that the experimentally observed range of p-values may be the result of, or at least be affected by DNA adsorption and friction between the DNA and the substrate surface.
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