We applied a simple, sensitive differential absorption technique to measure the two-photon cross section for the 5(2)S((1/2))(F(g) = 2) ? 5(2)D(5/2)(F(e) = 4) hyperfine transition in (85)Rb [sigma((2)) = (1.2 +/- 0.5) x 10(-18) cm(4)/W]. The detection circuit permitted straightforward measurements close to the shot-noise limit. Detailed quantitative analysis of the measurements shows excellent agreement with theory.
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http://dx.doi.org/10.1364/ol.18.001754 | DOI Listing |
Microsyst Nanoeng
March 2025
Department of Electrical and Electronics Engineering, Department of Physics, UNAM - National Nanotechnology Research Center and Institute of Materials Science and Nanotechnology, Bilkent University, Ankara, 06800, Turkey.
Three-dimensional (3D) printing allows for the construction of complex structures. However, 3D-printing vertical structures with a high aspect ratio remains a pending challenge, especially when a high lateral resolution is required. Here, to address this challenge, we propose and demonstrate micro-3D sculptured metastructures with deep trenches of 1:4 (width:height) aspect ratio for sub-10 µm resolution.
View Article and Find Full Text PDFMicroglia-mediated neuroinflammation is a key contributor to Parkinson's disease (PD) pathogenesis. Leucine-rich repeat kinase 2 (LRRK2), the leading genetic contributor to both familial and sporadic PD, has been implicated in driving this connection. However, its precise role remains incompletely understood due to technical challenges.
View Article and Find Full Text PDFJ Biophotonics
March 2025
Shanghai East Hospital, Tongji University School of Medicine, Shanghai, China.
Psoriasis is a global problem that significantly affects patients both physically and mentally. Accurate and rapid detection of psoriasis is crucial for diagnosis and treatment. Herein, we utilized multiphoton microscopy (MPM) to rapidly image psoriasis in imiquimod-induced mouse and human psoriatic samples.
View Article and Find Full Text PDFChemistry
March 2025
Instituto de Química, Universidad Nacional Autónoma de México, Ciudad de México, México.
Non-linear optical reactive systems have important applications which require highly localized effects. Recently, we reported for the first time that donor-acceptor Stenhouse adducts (DASAs) have important two-photon switching properties. Here, we report on the nature of the non-linear excitation event and the resulting dynamics through femtosecond-resolved measurements.
View Article and Find Full Text PDFProg Neurobiol
February 2025
School of Psychological and Cognitive Sciences, Peking University, Beijing, Beijing, China; IDG-McGovern Institute for Brain Research, Peking University, Beijing, China. Electronic address:
Surround modulation is a fundamental property of V1 neurons, playing critical roles in stimulus integration and segregation. It is believed to be orientation-specific, as neurons' responses at preferred orientations are suppressed more by iso-oriented surrounds than by cross-oriented surrounds. Here, we investigated an alternative hypothesis that surround modulation is primarily orientation-unspecific, in that the observed "orientation-specific" surround effects actually reflect overall gain changes that affect neurons tuned to all orientations.
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