Broadband spectral tuning in the long wavelength range (greater than 10 μm) was demonstrated with an external-cavity quantum cascade laser. The tunable wavelength of the laser ranged from 9.5 to 11.4 μm (176 cm(-1); corresponding to 18% of the center wavelength) in continuous wave (cw) operation at room temperature, without any anti-reflection coating. The gain chip based on the anti-crossed dual-upper-state (DAU) design provided a cw lasing up to 300 K, with a low threshold current density of 2.1 kA/cm2. The highly stable broadband spectral tuning and high laser performance were enabled by the spectrally homogeneous gain profile of the anti-crossed DAU active region.
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http://dx.doi.org/10.1364/OE.22.019930 | DOI Listing |
J Invest Surg
December 2025
Department of Surgery, University of Minnesota Twin Cities Medical School, Minneapolis, MN, USA.
Background: Venous waveform analysis is an emerging technique to estimate intravascular fluid status by fast Fourier transform deconvolution. Fluid status has been shown proportional to , the amplitude of the fundamental frequency of the waveform's cardiac wave upon deconvolution. Using a porcine model of distributive shock and fluid resuscitation, we sought to determine the influence of norepinephrine on of the central venous waveform.
View Article and Find Full Text PDFChaos
January 2025
Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306, USA.
Traveling waves of excitation arise from the spatial coupling of local nonlinear events by transport processes. In corrosion systems, these electro-dissolution waves relay local perturbations across large portions of the metal surface, significantly amplifying overall damage. For the example of the magnesium alloy AZ31B exposed to sodium chloride solution, we report experimental results suggesting the existence of a vulnerable zone in the wake of corrosion waves where local perturbations can induce a unidirectional wave pulse or segment.
View Article and Find Full Text PDFEur J Dent
December 2024
Department of Preventive and Restorative Dentistry, College of Dental Medicine, University of Sharjah, Sharjah, United Arab Emirates.
Objective: This study compares the color change of non-vital anterior teeth after laser-activated bleaching and conventional walking bleaching technique.
Materials And Methods: Sixty extracted teeth were endodontically treated, stained in a black tea solution, and the baseline shade was measured using a spectrophotometer (Easyshade, VITA). Bleaching was done using either: internal bleaching with 35% HO (Opalescence Endo) and then tooth sealed for 5 days (Gr1), 35% HO (JW Next) for 7 minutes (Gr2), internal and external bleaching for 7 minutes (Gr3), diode laser-activated internal bleaching for 30 seconds (940 nm, continuous wave, 2 W, noncontact mode, 300 um, non-initiated tip), wait for 7 minutes, second laser application for 30 seconds, tooth sealed for 5 days (Gr4), diode laser-activated internal bleaching for 24 hours (Gr5), or diode laser-activated internal and external bleaching for 24 hours (Gr6) ( = 10).
Mater Horiz
January 2025
School of Materials Science and Engineering, Energy Materials and Devices Key Lab of Anhui Province for Photoelectric Conversion, Anhui University, Hefei, Anhui 230601, China.
The triboelectric nanogenerator (TENG) has been proved to be a very promising marine energy harvesting technology. Herein, we have developed a high-performance triboelectric nanogenerator (SD-TENG) with low friction, high durability, swing-induced counter-rotating motion mechanism (SICRMM) and dual potential energy storage and release strategy (DPESRS). The unique counter-rotating motion mechanism enabled SD-TENG to convert the external linear and swing motion energy into rotation motion energy of the inner and outer cylinders, and then converted it into a controllable power output.
View Article and Find Full Text PDFNat Nanotechnol
January 2025
Wellman Center for Photomedicine, Massachusetts General Hospital, Cambridge, MA, USA.
The ultimate limit for laser miniaturization would be achieving lasing action in the lowest-order cavity mode within a device volume of ≤(λ/2n), where λ is the free-space wavelength and n is the refractive index. Here we highlight the equivalence of localized surface plasmons and surface plasmon polaritons within resonant systems, introducing nanolasers that oscillate in the lowest-order localized surface plasmon or, equivalently, half-cycle surface plasmon polariton. These diffraction-limited single-mode emitters, ranging in size from 170 to 280 nm, harness strong coupling between gold and InGaAsP in the near-infrared (λ = 1,000-1,460 nm), away from the surface plasmon frequency.
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