The frequency of a wavelength standard at 1542 nm (194 THz) developed in CMI for the telecommunication band C was measured with a fiber femtosecond frequency comb. The measurement was done for three transitions of acety(13)C(2)H(2): P(14), P(15) and P(16). The results agree well with values in the recommendation for Practical realization of the definition of the metre [1] and even better with recent measurements made in NMIJ/AIST [2,3] - the differences are lower than 2 kHz (or 1x10-(-11) rel.) for all three transitions. This agreement is significant considering the fact that the CMI laser uses an extremely simple spectroscopic arrangement and substantially lower saturation power.
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http://dx.doi.org/10.1364/opex.13.009196 | DOI Listing |
Sci Rep
January 2025
Hannover Centre for Optical Technologies (HOT), Leibniz University Hannover, Hannover, Germany.
Hyperspectral imaging (HSI) systems acquire images with spectral information over a wide range of wavelengths but are often affected by chromatic and other optical aberrations that degrade image quality. Deconvolution algorithms can improve the spatial resolution of HSI systems, yet retrieving the point spread function (PSF) is a crucial and challenging step. To address this challenge, we have developed a method for PSF estimation in HSI systems based on computed wavefronts.
View Article and Find Full Text PDFACS Appl Opt Mater
December 2024
Department of Physics, Umeå University, Linnaeus väg 24, 901 87 Umeå, Sweden.
Multilayered metal-dielectric nanostructures display both a strong plasmonic behavior and hyperbolic optical dispersion. The latter is responsible for the appearance of two separated radiative and nonradiative channels in the extinction spectrum of these structures. This unique property can open plenty of opportunities toward the development of multifunctional systems that simultaneously can behave as optimal scatterers and absorbers at different wavelengths, an important feature to achieve multiscale control of light-matter interactions in different spectral regions for different types of applications, such as optical computing or detection of thermal radiation.
View Article and Find Full Text PDFAnal Chem
January 2025
School of Optoelectronic Engineering and Instrumentation Science, Dalian University of Technology, Dalian 116024, Liaoning, China.
A cantilever-enhanced fiber-optic photoacoustic (PA) spectrophone is reported for trace gas detection at a low-pressure environment. A cantilever-based fiber-optic Fabry-Perot (F-P) interferometer (FPI) is utilized for simultaneous measurement of air pressure and PA pressure. Since the cantilever resonance frequency follows air pressure linearly, the fundamental frequency intensity modulation (1-IM) technique is applied to scan the frequency response of the solid PA signal from tube wall absorption for tracking the cantilever resonance frequency in real time.
View Article and Find Full Text PDFThe broad spectrum of clinical manifestations caused by peripheral arterial disease [PAD] and the morphologic heterogeneity of associated atherosclerotic lesions present a considerable management challenge. Endovascular interventions are recognized an effective treatment for PAD. Within this revascularization strategy the role of atherectomy debulking modalities continue to evolve.
View Article and Find Full Text PDFEcotoxicol Environ Saf
December 2024
Centre de Recherche des Cordeliers, INSERM UMRS 1138, Université Paris Cité, Sorbonne Université. Team: Physiopathology of Ocular Diseases: Therapeutic Innovations. 15, rue de l'école de Médecine Paris 75006, France. Electronic address:
The exposure of the general population to artificial light at night has dramatically increased in recent decades. Current standards for domestic lighting are based on acute exposure to light and consider blue wavelengths to be responsible for phototoxicity. However, meta-analyses pointed out the role of lifelong light exposure in the onset of age-related macular degeneration, suggesting a cumulative effect of light exposure.
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