Two approaches are presented for the analysis of laser action in periodic structures. The first one uses the coupled-wave formalism to analyze guided-wave propagation in a periodic waveguide defined by the coupling coefficient and the conditions at the cavity ends. The second analysis is based on...
The absorption cross section was estimated to be2.8×1016cm2at the absorption peakλ=370nm.Gain and loss measurements at the ASE peak showed that the net gain coefficient reaches26±1.7cm1when pumped at1.4KW/cm2,and the loss coefficient of the waveguide was about13±1.1cm1. 展开 ...
threshold gain margins longitudinal photon-density distributions three-section corrugation-pitch-modulated DFB laser distributed-coupling-coefficient above-threshold numerical simulations very good single-mode operation correct optimisation Bragg detuning coupling strength profile high injection currents/ A4255B ...
The threshold of a laser is the state where the small-signal gain just equals the resonator losses, so that laser emission can just begin. This is the case for a certain pump power (the threshold pump power), or (for electrically pumped lasers) a certain threshold current. Significant ...
Despite the fact that silica has a much smaller Raman gain coefficient than other materials in similar studies, such as CS2 microdroplets, its very high Q-factor ensured that even a low input power remained trapped long enough in the cavities to build to the necessarily high intensities. In ...
in contrast to the other BIC modes. We also show that for finite-size resonators the optimal lattice constant providing the lowest radiation is shifted compared to the infinite-size structure. After the transition to the super-BIC regime, we measure the far-field laser image with strong angular...
optical gain thresholds and lead to record-long stable ASE. Employing specifically engineered core/crown@gradient-alloyed shell heterostructures, we present a linearly polarized single-mode lasing from a vertical-cavity surface-emitting laser enabling a record low lasing threshold of ~7.46 μJ cm...
SLO 101 (and SLO 102) 1990 Rodenstock SLO – IR (infrared diode laser [780 nm]) Fundus Autofluorescence, fluorescein angiography, Indocyanine green angiography 33 °× 21 ° 0–21 dB 50 Hz 10 cd/m2 71 cd/cm2 Helium–Neon laser beam (632.8 nm)Argon-Laser (488 nm and 514 nm) NIDEK ...
Gain is low and the region of ordinary lasing above threshold is pushed too far towards high energy and beyond the limits of the available laser and probably the dye tolerance. However, the intensity fluctuation at the threshold was observed for all the samples. When the threshold is low ...
LAO films were grown by pulsed laser deposition (PLD) on TiO2-terminated STO(001) substrates and followed by in situ magnetron sputtering deposition of a 2–2.5-nm cobalt thin film, capped with a 3-nm AlOx layer to prevent Co oxidation. Details concerning samples fabrication and ...