A static electric field enables coherent control of the photoexcited carrier density in a semiconductor through the interference of one- and two-photon absorption. An experiment using optical detection is described. The polarization dependence of the signal is consistent with a calculation using a 14-band k · p model for GaAs. We also describe an electrical measurement. A strong enhancement of the phase-dependent photocurrent through a metal-semiconductor-metal structure is observed when a bias of a few volts is applied. The dependence of the signal on bias and laser spot position is studied. The field-induced enhancement of the signal could increase the sensitivity of semiconductor-based carrier-envelope phase detectors, useful in stabilizing mode-locked lasers for use in frequency combs.
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http://dx.doi.org/10.1364/OE.19.022563 | DOI Listing |
Front Med (Lausanne)
January 2025
Ophthalmology Department, Medical University of Bialystok, Bialystok, Poland.
Purpose: Systemic sclerosis (SSc) affects blood vessels, internal organs, and skin. In ophthalmology, SSc impacts the choroid. The choroidal vascularity index (CVI) measures the vascular component of the choroid and may serve as a biomarker for the disease staging and prognosis.
View Article and Find Full Text PDFPrecis Chem
January 2025
Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan.
Organic semiconducting nanomembranes (OSNMs), particularly carbon-based ones, are at the forefront of next-generation two-dimensional (2D) semiconductor research. These materials offer remarkable promise due to their diverse chemical properties and unique functionalities, paving the way for innovative applications across advanced semiconductor material sectors. Graphene stands out for its extraordinary mechanical strength, thermal conductivity, and superior charge transport capabilities, inspiring extensive research into other 2D carbon allotropes like graphyne and graphdiyne.
View Article and Find Full Text PDFBackground: To evaluate the associations between anatomical changes and visual outcomes after membrane peeling in eyes with different stages of idiopathic epiretinal membrane (iERM) using optical coherence tomography angiography (OCTA).
Methods: All iERM eyes were graded into four stages based on the presence of ectopic inner foveal layers (EIFL) and underwent 23-gauge vitrectomy combined with ERM and internal limiting membrane (ILM) peeling, while their fellow eyes were treated as the control group. OCTA was used to measure retinal thickness(RT), foveal avascular zone (FAZ)-related parameters and superficial and deep capillary plexus (SCP and DCP) layers using 6 × 6 mm scans before, 1 month and 3 months after surgery.
Nat Commun
January 2025
School of Integrated Circuits and Frontier Science Center for Quantum Information, Tsinghua University, Beijing, China.
Cubic silicon-carbide crystals (3C-SiC), known for their high thermal conductivity and in-plane stress, hold significant promise for the development of high-quality (Q) mechanical oscillators. We reveal degeneracy-breaking phenomena in 3C-phase crystalline silicon-carbide membrane and present high-Q mechanical modes in pairs or clusters. The 3C-SiC material demonstrates excellent microwave compatibility with superconducting circuits.
View Article and Find Full Text PDFGraefes Arch Clin Exp Ophthalmol
January 2025
Department of Ophthalmology and Optometry, Medical University of Vienna, Vienna, Austria.
Purpose: To investigate the role of corneal epithelium- and Bowman's layer-thickness (ET and BLT) changes as possible early biomarkers of keratoconus (KC) development.
Methods: In this cross-sectional study patients with unilateral KC (UKC) and a group of healthy controls underwent polarization sensitive optical coherence tomography (PS-OCT) for the evaluation of corneal ET and BLT. These values were compared among three subgroups of eyes, i.
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