ABSTRACT
In this erratum we clarify our previously published paper [Appl. Opt.57, 4008 (2018)APOPAI0003-693510.1364/AO.57.004008], where we used a solar spectrum truncated to a maximum wavelength of 830 nm in the numerical modelling, but did not state this in the paper. Here, we present a graph of the numerically modelled absorption in the Nd:YAG rod as a function of the diffuse reflectivity of the chamber walls using the full solar spectrum, confirming that the theoretical maximum possible absorption we predict is in agreement with literature values.
ABSTRACT
We report a solar pumped solid state laser using a 20 mm long, 3 mm diameter neodymium-doped yttrium aluminum garnet laser rod. This rod was placed in a liquid cooling chamber using a water-white-emulsion-paint mix. This mix provides cooling for the laser crystal and also doubles as a diffuse light scattering liquid. This enhances sunlight scattering and leads to a greater absorption in the laser rod. We numerically model the solar absorption in the laser rod using a ray-tracing model and predict a 2.6 times enhancement in absorption when a 98% reflective diffuse scatter is modelled compared to 0% scattering. We experimentally demonstrated this, showing a 2.58 times increase in average output power of the solar laser compared to the use of pure water as a cooling liquid. Using the water-white-paint scattering cooling liquid, we demonstrated a laser with an output power of 2.3 W and with a collection efficiency of 27.5 W/m2.
ABSTRACT
We report the generation of high-peak-power picosecond optical pulses in the 1.55 µm spectral band from a monolithically mode-locked laser integrated with a pulse selector and power booster. High-peak-power (>1 W) pulses with durations of 15.4 ps at a 55 MHz selected rate are demonstrated, indicating that this device shows promise as a high-peak-power pulsed light source for bio-photonic applications.
ABSTRACT
Terahertz (THz) radiation can be generated by ultrafast photo-excitation of carriers in a semiconductor partly masked by a gold surface. A simulation of the effect taking into account the diffusion of carriers and the electric field shows that the total net current is approximately zero and cannot account for the THz radiation. Finite element modelling and analytic calculations indicate that the THz emission arises because the metal inhibits the radiation from part of the dipole population, thus creating an asymmetry and therefore a net current. Experimental investigations confirm the simulations and show that metal-mask dipole inhibition can be used to create THz emitters.
ABSTRACT
The interaction of an optical pulse with a quantum well saturable absorber is simulated using a semi-classical two-level-atom model which has been modified to approximate spectral hole burning in the carrier distribution. Saturable absorption behaviour is examined in the limit where pulse duration approaches the carrier-carrier scattering time. For long pulses bleaching dominates the absorber response but as the pulse duration approaches the carrier-carrier scattering timescale an additional pulse shaping mechanism becomes active, allowing the absorber to continue to shorten pulses beyond the limit set by bleaching. Examination of the spectral and temporal absorption profiles suggests that intense pulses experience additional pulse shortening from the optical Stark effect.
Subject(s)
Light , Models, Theoretical , Refractometry/methods , Scattering, Radiation , Surface Plasmon Resonance/methods , Absorption , Computer SimulationABSTRACT
We present a method to experimentally characterize the gain filter and calculate a corresponding parabolic gain bandwidth of lasers that are described by "class A" dynamics by solving the master equation of spectral condensation for Gaussian spectra. We experimentally determine the gain filter, with an equivalent parabolic gain bandwidth of up to 51 nm, for broad-band InGaAs/GaAs quantum well gain surface-emitting semiconductor laser structures capable of producing pulses down to 60 fs width when mode-locked with an optical Stark saturable absorber mirror.
