We report on single-longitudinal-mode (SLM) operation of a low-threshold optical parametric oscillator, with a 17 nm tunability near 2 µm. The oscillator uses a MgO:PPLN crystal in Type 0 quasi-phase-matching configuration, pumped by a 1.064 µm SLM laser. Despite the huge acceptance bandwidth near-degeneracy of MgO:PPLN, spectral selection down to a SLM is achieved by combining a volume Bragg reflector and Vernier filtering in nested signal and idler cavities. Tunability over 17 nm is demonstrated owing to a transverse chirp of the grating period of the Bragg reflector.
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http://dx.doi.org/10.1364/OL.379581 | DOI Listing |
Sci Rep
January 2025
Preparatory Institute for Engineering Studies of Kairouan, (I.P.E.I.K) University of Kairouan, Kairouan, Tunisia.
We present a comprehensive analysis of the optical attributes of graphene sheets with charge carriers residing on a curved substrate. In particular, we focus on the fascinating case of Beltrami geometry and provide an explicit parametrization for this curved two-dimensional surface. By employing the massless Dirac description that is characteristic of graphene, we investigate the impact of the curved geometry on the optical properties within the sample.
View Article and Find Full Text PDFJ Chem Phys
January 2025
Department of Chemistry, Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
We present velocity-map imaging (VMI) of photoelectrons detached from anions using an optical parametric amplifier operating at a repetition rate as high as 100 kHz. The light source generates femtosecond (fs) laser pulses tunable from near-infrared to ultraviolet (310-2600 nm), which interact synchronously with mass-selected anion bunches. We demonstrate this technique by measuring two-dimensional projections of photoelectrons ejected from silver trimer anions, Ag3-, across a photon energy range from 2.
View Article and Find Full Text PDFJ Dent
January 2025
Clinic of General-, Special Care- and Geriatric Dentistry, Center for Dental Medicine, University of Zurich, Zurich, Switzerland. Electronic address:
Objectives: The study aimed to assess the prevalence and nature of emotional expressions in care-dependent older adults, using an automated face coding (AFC) software. By examining the seven fundamental emotions, the study sought to understand how these emotions manifest and their potential implications for dental care in this population.
Methods: Fifty care-dependent older adults' (mean-age: 78.
Ophthalmic Physiol Opt
January 2025
Department of Optometry and Vision Science, Hadassah Academic College, Jerusalem, Israel.
Purpose: Reliable assessment is critical for diagnosing and managing meibomian gland dysfunction. Multi-functional diagnostic devices, such as meibographers, streamline clinical workflows by integrating multiple ocular assessments. Ensuring reproducibility across examiners is vital for accurate diagnosis and monitoring of treatment.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Chemical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.
In this paper, we propose and theoretically investigate a novel multimode refractive index (MMRI) plasmonic optical sensor for detecting various brain cancer cells, leveraging the unique capabilities of split ring resonators (SRRs). The sensor, simulated using the finite-difference time-domain (FDTD) method, exhibits dual resonance modes in its reflection spectrum within the 1500 nm to 3500 nm wavelength range, marking a significant advancement in multimode plasmonic biosensing. Through detailed parametric analysis, we optimize critical dimensional parameters to achieve superior performance.
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