We report on the Doppler-free saturation spectroscopy of a molecular transition at 3.3 THz based on a quantum-cascade laser and an absorption cell in a collinear pump-probe configuration. A Lamb dip with a sub-Doppler linewidth of 170 kHz is observed for a rotational transition of HDO. We found that a certain level of external optical feedback is tolerable as long as the free spectral range of the external cavity is large compared to the width of the absorption line.
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http://dx.doi.org/10.1364/OE.26.006692 | DOI Listing |
Chirality
January 2025
JASCO Corporation, Japan.
A vibrational circular dichroism (VCD) instrument having a thermoelectrically cooled detector (denoted as a TEC unit) was constructed in this study. An electronic device, instead of liquid nitrogen, was employed in the instrument to cool the detector. The feasibility of the system was examined by recording the VCD spectra of liquid pinenes and insect wings.
View Article and Find Full Text PDFBMC Oral Health
January 2025
Associate Professor of Operative Dentistry, Conservative Dentistry Department, Faculty of Oral and Dental Medicine Badr University in Cairo, Cairo, Egypt.
Background: Endodontic treatment aims in the preservation of extremely carious primary teeth. For root canal therapy to be successful, root canals must be properly prepared and effectively irrigated .Therefore, it is necessary to select the proper root canal disinfection method to preserve the primary tooth.
View Article and Find Full Text PDFJ Indian Soc Pedod Prev Dent
October 2024
Department of Pediatric and Preventive Dentistry, Maratha Mandal's Nathajirao G. Halgekar Institute of Dental Sciences and Research Centre, Belagavi, Karnataka, India.
Background And Objectives: The purpose of this study was to evaluate the antimicrobial activity of methylene blue dye with 660-nm diode laser in cavity disinfection and to compare the total bacterial count in dentinal samples preexcavation, postexcavation, and postdisinfection. The study design was experimental in vivo.
Materials And Methods: Fifteen children aged 5-12 years with 15 primary molars requiring atraumatic restorative treatment (ART) were selected.
Sensors (Basel)
December 2024
College of Physics and Electronic Engineering, Hainan Normal University, Haikou 571158, China.
Fiber Bragg gratings (FBGs) are widely used in stress and temperature sensing due to their small size, light weight, high resistance to high temperatures, corrosion, electromagnetic interference, and low cost. In recent years, various structural enhancements and sensitization to FBGs have been explored to improve the performance of ocean temperature and depth sensors, thereby enhancing the accuracy and detection range of ocean temperature and depth data. This paper reviews advancements in temperature, pressure, and dual-parameter enhancement techniques for FBG-based sensors.
View Article and Find Full Text PDFSci Adv
January 2025
State Key Laboratory of Extreme Photonics and Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou 310027, China.
Solution-processed semiconductor lasers are next-generation light sources for large-scale, bio-compatible and integrated photonics. However, overcoming their performance-cost trade-off to rival III-V laser functionalities is a long-standing challenge. Here, we demonstrate room-temperature continuous-wave perovskite polariton lasers exhibiting remarkably low thresholds of ~0.
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