Real-time Image Denoising of Mixed Poisson-Gaussian Noise in Fluorescence Microscopy Images using ImageJ

Fluorescence microscopy imaging speed is fundamentally limited by the measurement signal-to-noise ratio (SNR). To improve image SNR for a given image acquisition rate, computational denoising techniques can be used to suppress noise. However, analytical techniques to estimate a denoised image from a single frame are either computationally expensive or rely on simple noise statistical models. These models assume Poisson or Gaussian noise statistics, which are not appropriate for many fluorescence microscopy applications that contain quantum shot noise and electronic Johnson-Nyquist noise, and therefore a mixture of Poisson and Gaussian noise. In this paper, we show convolutional neural networks (CNNs) trained on mixed Poisson and Gaussian noise images to overcome the limitations of existing image denoising methods. The trained CNN is presented as an open-source ImageJ plugin that performs instant image denoising (within tens of milliseconds) with superior performance (~8.1 dB SNR improvement) compared to the conventional fluorescence microscopy denoising methods. The method is validated on external datasets with out-of-distribution noise and contrast from the training data and consistently achieves high performance (>8dB) denoising in less time than other fluorescence microscopy denoising methods.

Cavity-enhanced microwave readout of a solid-state spin sensor

Overcoming poor readout is an increasingly urgent challenge for devices based on solid-state spin defects, particularly given their rapid adoption in quantum sensing, quantum information, and tests of fundamental physics. However, in spite of experimental progress in specific systems, solid-state spin sensors still lack a universal, high-fidelity readout technique. Here we demonstrate high-fidelity, room-temperature readout of an ensemble of nitrogen-vacancy centers via strong coupling to a dielectric microwave cavity, building on similar techniques commonly applied in cryogenic circuit cavity quantum electrodynamics. This strong collective interaction allows the spin ensemble’s microwave transition to be probed directly, thereby overcoming the optical photon shot noise limitations of conventional fluorescence readout. Applying this technique to magnetometry, we show magnetic sensitivity approaching the Johnson–Nyquist noise limit of the system. Our results pave a clear path to achieve unity readout fidelity of solid-state spin sensors through increased ensemble size, reduced spin-resonance linewidth, or improved cavity quality factor.

Development of Thermal Detector Based on Flexible Film Thermoelectric Module

Thermal detectors find a significant niche in the market of modern sensors. Bi2T3 and PbTe semiconductors are effective thermoelectrics and excellent candidates for different applications. In the present work, a technology for fabrication of p-Bi0.5Sb1.5Te3 and n-PbTe films with the high thermoelectric efficiency on thin flexible polyimide substrate has been developed. The preparation of films was performed by flash evaporation method. The high sensitivity of the devices is due to the high Seebeck coefficient of 200 mV/K and reduction of thermal conductivity of thin thermoelectric film from the bulk value. The devices operate in the Johnson-Nyquist noise limit of the thermocouple. The performance enables fast and sensitive detection of low levels of thermal power and infrared radiation at room temperature.

The Puzzling of Zero-Point Energy Contribution to Black-Body Radiation Spectrum: The Role of Casimir Force

The role played by zero-point contribution in black-body radiation spectrum is investigated in connection with the presence of Casimir force. We assert that once mechanical stability for the physical system is established, there is no further role for zero-point contribution to the spectrum in full agreement with experimental evidence. As a direct consequence, Johnson–Nyquist noise in dissipative conductors, should be interpreted just in terms of thermal fluctuations only, thus neglecting quantum fluctuations predicted by [H. Callen and T. Welton, Irreversibility and generalized noise, Phys. Rev. 83 (1951) 34]. Casimir force between opposite metallic plates can be independently measured by its equilibration through application of a mechanical force and measuring it at a mechanical equilibrium.

Joint Effect of Heterogeneous Intrinsic Noise Sources on Instability of MEMS Resonators

This article's focus is on the numerical estimation of the overall instability of microelectromechanical-system-based (MEMS) resonators, caused by intrinsic noise mechanisms that are different in nature (electrical, mechanical or chemical). Heterogeneous intrinsic noise sources in MEMS resonators that have been addressed here are Johnson–Nyquist noise, 1/f noise, noise caused by temperature fluctuations and adsorptiondesorption induced noise. Their models are given first (based on analytical modeling or based on empirical expressions with experimentally obtained parameters). Then it is shown how each one contributes to the phase noise, a unique figure of merit of resonators instability. Material dependent constants  and knee position in noise spectrum, needed for empirical formulae referring to 1/f noise, have been obtained experimentally, by measurements of noise of MEMS components produced in the Centre of Microelectronic Technologies of the Institute of Chemistry, Technology and Metallurgy in Belgrade. According to these measurements,  varies in the range from 0.776.10-4 to 2.26.10-4 and cut off frequency for 1/f noise varies from 147 Hz to 1 kHz. The determined values are then used for the modeling of micro-resonator phase noise with electrical origin and overall phase noise of a micro-resonator. Numerical example for calculation of overall phase noise is given for a micro-cantilever, produced by the same technology as measured components. The outlined noise analysis can be easily extended and applied to noise analysis of MEMS resonator of an arbitrary shape.