We report the laser-diode pumped multi-gigahertz (GHz) self-mode-locked alexandrite femtosecond (fs) lasers for the first time, to the best of our knowledge. Using a simple linear cavity, stable mode-locked laser was achieved with a repetition rate of 3.6 GHz and a pulse width of 237 fs. Additionally, the second-harmonic mode-locked pulse was realized with a repetition rate of 7.5 GHz and a pulse width of 201 fs based on the Fabry-Perot effect generated in the laser cavity. It was observed that this laser possesses advantages of high repetition rate and short pulse width that enable the development of promising applications in modern ultrafast photonics.
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http://dx.doi.org/10.1364/OL.423249 | DOI Listing |
J 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 PDFAlzheimers Dement
December 2024
Penn FTD Center, University of Pennsylvania, Philadelphia, PA, USA.
Background: Comorbid cognitive impairment in amyotrophic lateral sclerosis (i.e., ALS-FTD), is associated with adverse clinical outcomes and survival.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
Background: The ability to monitor cognitive trajectories over the course of trials can provide valuable insights into treatment efficacy. However, existing trial methods are limited in monitoring cognition in real-time and at high frequencies. Gameplay-based assessments hold promise as complementary cognitive tools.
View Article and Find Full Text PDFIntroduction: Evaluation of functional dependence in activities of daily living (ADLs) and instrumental activities of daily living (iADLs) is necessary for dementia diagnosis. ADL and iADL questionnaires are typically employed, but with progressive cognitive impairment, a care partner must step in to assist with these tests, causing logistical burdens. Pre-screening tools that triage patients in need of formal functional assessment would optimize clinical workflows.
View Article and Find Full Text PDFActa Neurochir (Wien)
January 2025
Department of Neurosurgery, University Medicine Greifswald, Greifswald, Germany.
Purpose: Currently available grading and classification systems for hemifacial spasm either rely on subjective assessments or are excessively intricate. Here, we make use of facial recognition and facial tracking technologies towards accurately grouping patients according to severity and characteristics of the spasms.
Methods: A retrospective review of our prospectively maintained preoperative videos database for hemifacial spasm was done.
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