Presented here is the development and demonstration of a tunable cavity-enhanced terahertz (THz) frequency-domain optical Hall effect (OHE) technique. The cavity consists of at least one fixed and one tunable Fabry-Pérot resonator. The approach is suitable for the enhancement of the optical signatures produced by the OHE in semi-transparent conductive layer structures with plane parallel interfaces. Tuning one of the cavity parameters, such as the external cavity thickness, permits shifting of the frequencies of the constructive interference and provides substantial enhancement of the optical signatures produced by the OHE. A cavity-tuning optical stage and gas flow cell are used as examples of instruments that exploit tuning an external cavity to enhance polarization changes in a reflected THz beam. Permanent magnets are used to provide the necessary external magnetic field. Conveniently, the highly reflective surface of a permanent magnet can be used to create the tunable external cavity. The signal enhancement allows the extraction of the free charge carrier properties of thin films and can eliminate the need for expensive superconducting magnets. Furthermore, the thickness of the external cavity establishes an additional independent measurement condition, similar to, for example, the magnetic field strength, THz frequency, and angle of incidence. A high electron mobility transistor (HEMT) structure and epitaxial graphene are studied as examples. The tunable cavity-enhancement effect provides a maximum increase of more than one order of magnitude in the change of certain polarization components for both the HEMT structure and epitaxial graphene at particular frequencies and external cavity sizes.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1063/5.0010267 | DOI Listing |
Health Care Sci
December 2024
Centre for Quantitative Medicine, Duke-NUS Medical School Singapore.
Background: Pneumothorax is a medical emergency caused by the abnormal accumulation of air in the pleural space-the potential space between the lungs and chest wall. On 2D chest radiographs, pneumothorax occurs within the thoracic cavity and outside of the mediastinum, and we refer to this area as "lung + space." While deep learning (DL) has increasingly been utilized to segment pneumothorax lesions in chest radiographs, many existing DL models employ an end-to-end approach.
View Article and Find Full Text PDFAcad Radiol
December 2024
Department of Otorhinolaryngology, Head and Neck Surgery, Yantai Yuhuangding Hospital, Qingdao University, Yantai, China (Y.W., P.Y., J.W., Z.Z., G.W., Y.Z., Y.Y., Y.M., X.S.); Shandong Provincial Clinical Research Center for Otorhinolaryngologic Diseases, Yantai Yuhuangding Hospital, Yantai, China (Y.W., P.Y., J.W., Z.Z., G.W., Y.Z., Y.Y., Y.M., X.S.); Yantai Key Laboratory of Otorhinolaryngologic Diseases, Yantai Yuhuangding Hospital, Yantai, China (Y.W., P.Y., J.W., Y.Z., Y.Y., Y.M., X.S.). Electronic address:
Rationale And Objectives: Nasal polyps (NP) and inverted papilloma (IP) are benign tumors within the nasal cavity, each necessitating distinct treatment approaches. Herein, we investigate the utility of a deep learning (DL) model for distinguishing between NP and IP.
Materials And Methods: A total of 1791 patients with nasal benign tumors from two hospitals were retrospectively enrolled.
J Craniofac Surg
October 2024
School of Medicine, Wayne State University.
A pseudoaneurysm is an abnormal dilatation within the wall of a blood vessel due to the formation of a hematoma in the vessel wall after vessel injury. Because of the protective nature of the facial skeleton and the deep location of the lingual artery, the lingual artery pseudoaneurysm is rare. The authors report a case of a 20-year-old male who suffered multiple gunshot wounds, including to the mouth, presenting with immediate life-threatening injuries.
View Article and Find Full Text PDFJ Hum Evol
December 2024
Univ. Paris 1 Panthéon-Sorbonne, Univ. Paris Ouest Nanterre La Défense, MSH Mondes-CNRS-Ministère de la Culture, ArScAn, UMR 7041, 92000, Nanterre, France.
The Grotte du Bison, in Arcy-sur-Cure (Yonne, France), yielded a large assemblage of 49 Neandertal remains from late Mousterian layers, offering critical insights for the study of Middle to Upper Paleolithic populations of Western Europe. Previous studies described the external morphology of 13 isolated teeth and a partial maxilla. Building on this previous work, the current study provides further descriptions and analyses of the remains, including one postcranial fragment, six cranial fragments, two maxillary fragments, and 40 isolated teeth.
View Article and Find Full Text PDFWe experimentally demonstrate a cost-effective dual-polarization quadrature phase shift keying (DP-QPSK) coherent passive optical network (PON) system that operates at 100 Gbits/s/λ. This system utilizes distributed feedback lasers (DFBs) and a carrier recovery algorithm facilitated by a bifunctional frequency-domain pilot tone (FPT). To reduce costs in coherent PON implementations, low-cost DFBs are employed as the sole light sources, replacing the more expensive external cavity lasers (ECLs) at both the optical line terminal (OLT) and the optical network units (ONUs).
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!