Intensity noise characteristics of a single-mode Brillouin fiber ring laser are experimentally analyzed from 100 kHz up to 18 GHz. The Stokes wave is shown to be shot-noise limited to -155 dB/Hz for a 1 mA detected photocurrent over the whole spectral range 100 MHz-18 GHz. The pump-to-Stokes noise filtering efficiency is evaluated by artificially increasing the pump intensity noise. It evidences that a shot-noise-limited Brillouin laser could be realized by using a narrow-linewidth semiconductor laser pump, for stringent microwave photonics applications.
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http://dx.doi.org/10.1364/ol.33.001681 | DOI Listing |
ACS Appl Nano Mater
March 2024
Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States.
Photon-counting mammography is an emerging modality that allows for spectral imaging and provides a differentiation of material compositions. The development of photon-counting mammography-specific contrast agents has yet to be explored. In this study, the contrast, sensitivity, and organ dose between silver sulfide nanoparticles (AgS-NPs) and a clinically approved iodinated agent (iopamidol) were investigated using a contrast-embedded gradient ramp phantom and a prototype scanner.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
December 2024
Department of Physics and Engineering, Albany State University, GA 31707. USA. Electronic address:
This work represents a comprehensive study of the ground vibrational state of C-13 substituted methanol using very high-resolution far-infrared (FIR) and infrared (IR) Synchrotron Radiation spectra recorded with a very high signal-to-noise (S/N) ratio in the entire region from 40to5000cm, at the Canadian Light sources. High resolution combined with a high S/N ratio allowed the recording to be done with an unprecedented resolution of about 0.0017cm.
View Article and Find Full Text PDFAnal Chem
January 2025
School of Electrical Engineering, Yanshan University, Qinhuangdao 066004, China.
As breath nitric oxide (NO) is a biomarker of respiratory inflammation, reliable techniques for the online detection of ppb-level NO in exhaled breath are essential for the noninvasive diagnosis of respiratory inflammation. Here, we report a breath NO sensor based on the multiperiodic spectral reconstruction neural network. First, a spectral reconstruction method that transforms a spectrum from the wavelength domain to the intensity domain is proposed to remove noise and interference signals from the spectrum.
View Article and Find Full Text PDFAcross the scientific realm, we find ourselves subtracting or dividing stochastic signals. For instance, consider a stochastic realization, $x$, generated from the addition or multiplication of two stochastic signals $a$ and $b$, namely $x=a+b$ or $x = ab$. For the $x=a+b$ example, $a$ can be fluorescence background and $b$ the signal of interest whose statistics are to be learned from the measured $x$.
View Article and Find Full Text PDFFor the application scenario of multi-user, high-bandwidth laser communication in satellite internet, this paper proposes a spatiotemporal vector optimization algorithm to achieve high energy utilization in arbitrary multi-beam generation using a liquid crystal optical phased array antenna. The core components of this method involve optimizing phase offsets and power coefficients through iterative processes to achieve precise beam shaping and efficient energy distribution among multiple beams. This approach overcomes the single-link limitation of traditional laser terminals and resolves challenges such as low radiation efficiency and substantial power loss in multi-beam generation systems utilizing passive phased array antennas.
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