A tunable double-mode external cavity InAs/InP quantum dot laser based on a dual-Littrow configuration is demonstrated. A 115 nm single-mode tuning spectrum with obviously varied mode intensity has been obtained. A modified tuning method has been adopted to realize continuously tunable mode-spacing between two modes. It is found that single and double modes coexist in the tuning spectrum when one grating angle is fixed while the other grating is rotated; the biggest mode-spacing between double modes is about 75 nm. A continuously tunable range of mode-spacing between double wavelengths has reached up to 80 nm by inserting an attenuation slice in the external optical feedback paths to balance the intensity of the double modes; the separation of double modes is about 50 nm at best. The average output power of the double-mode laser is about a few milliwatts.
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http://dx.doi.org/10.1364/AO.56.006846 | DOI Listing |
Brain
January 2025
Department of Psychiatry (UPK), University of Basel, 4001 Basel, Switzerland.
Perception integrates external sensory signals with internal predictions that reflect prior knowledge about the world. Previous research suggests that this integration is governed by slow alternations between an external mode, driven by sensory signals, and an internal mode, shaped by prior knowledge. Using a double-blind, placebo-controlled, cross-over experiment in healthy human participants, we investigated the effects of the N-Methyl-D-aspartate receptor (NMDAR) antagonist S-ketamine on the balance between external and internal modes.
View Article and Find Full Text PDFWe develop fs laser-fabricated asymmetric couplers and zig-zag arrays consisting of single- and two-mode waveguides with bipartite Kerr nonlinearity in borosilicate (BK7) glass substrates. The fundamental mode ( orbital) is near resonance with the neighboring higher-order orbital, causing efficient light transfer at low power. Due to Kerr nonlinearity, the coupler works as an all-optical switch between and orbitals.
View Article and Find Full Text PDFSci Rep
January 2025
Key Laboratory of Optoelectronic Sensing and Intelligent Control, Hubei University of Science and Technology, Xianning, 437100, China.
We present a novel approach to realize three-dimensional (3D) matter wave solitons (MWSs) transformation between different optical potential wells by manipulating their depths and centers. The 3D MWSs are obtained by the square operator method, and transformed to other types (elliptical/ring/necklace) by performing time evolution with the split-step Fourier method. The effectiveness and reliability of our approach is demonstrated by comparing the transformed solitons with those obtained iteratively using the square operator method.
View Article and Find Full Text PDFAm J Infect Control
January 2025
Department of Population Health Sciences, School of Public Health, Georgia State University, Atlanta, GA. Electronic address:
Background: Personal protective equipment (PPE) doffing protocols can reduce risks of pathogen self-contamination. Powered air purifying respirators (PAPRs) may increase these risks. This study compares viral contamination and errors during simulated doffing of single layer vs double layer hood PAPRs.
View Article and Find Full Text PDFFood Chem
January 2025
School of Food and Biological Engineering, Key Laboratory for Animal Food Green Manufacturing and Resource Mining of Anhui Province, Engineering Research Center of Bio-Process, Ministry of Education, Hefei University of Technology, Hefei 230009, China. Electronic address:
Ultra-precision point-of-care detection of Escherichia coli O157:H7 in foods is an important issue. Here, the detection sensitivity was improved by a signal cascade amplification strategy synergised by exonuclease III assisted isothermal amplification and reverse magnetic strategy. The double-stranded DNA formed by the aptamer and the target DNA as a sensing switch, avoiding the complex process of specific nucleic acid extraction.
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