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The emission wavelength of broad-area AlGaInP/InGaP quantum-well lasers is tuned by the application of high hydrostatic pressure and low temperature from 645 down to 575 nm, i.e., from the red through the orange to yellow spectral range. Emission powers up to 300 mW are obtained in the full tuning range. The pressure and temperature dependence of threshold currents indicates that leakage occurs into the L and X minima in the barriers. [ABSTRACT FROM AUTHOR]

The photon density required for the saturation of normal-mode coupling in oxide-apertured nanocavities is measured to be 90 photons/μm2 by pump-probe experiments. The photon number is only 300 for a semiconductor nanocavity with a 2 μm diameter aluminum-oxide aperture, drastically reduced from 200 000 for a 50 μm waist on a planar microcavity. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The quantum mechanical nature of the light field in semiconductor microcavities leads to non-classical coupling effects between photons and electron–hole excitations. It is shown that these quantum correlations give rise to characteristic corrections of the semiclassical light-matter coupling dynamics. Examples of quantum correlation signatures include entanglement effects in the probe reflection of a microcavity system and squeezing in the incoherent emission. [ABSTRACT FROM AUTHOR]

In each of three experiments, each subject in each condition received five successive short-term memory (STM) tests with phonemically similar consonant trigrams as the items to be remembered. The retention interval for tests 1–4 of all conditions in the three experiments was held constant at 16.5 sec. On test 5 the retention interval was varied across conditions with the three experiments exploring retention intervals in the range 1–21.5 sec. In all three experiments little, if any, forgetting was observed on test 1; in all three experiments proactive interference (PI) was observed to develop across tests. Analysis of the test 5 data indicated that the PI effect of prior test items upon the test 5 target item reached a maximum by 6.5 sec., with no further forgetting beyond this interval. The test 5 data also suggested a reminiscence effect at the longest retention interval of 21.5 sec. The implications of the data for a theory of PI in STM are discussed. [ABSTRACT FROM AUTHOR]

The monolithic integration of pump lasers and optically pumped vertical-external-cavity surface-emitting lasers is demonstrated. An innovative contacting scheme for the pump lasers offers high design flexibility and scalability. First devices at 1000 nm generate output powers of 2.5 W in pulsed and 0.65 W in continuous-wave operation. [ABSTRACT FROM PUBLISHER]

Low threshold cw laser emission from a semiconductor disk laser emitting at 1260 nm was demonstrated. Using high quality metal-organic vapor phase epitaxy (GaIn) (NAs) material, nonradiative processes could be minimized. As a consequence, threshold pump power densities have been reduced down to 5 kW/cm2. The capture efficiency of carriers into the quantum wells was found to be uncritical. [ABSTRACT FROM AUTHOR]

Facet temperature changes in broad-area red-emitting high-power AlGaInP lasers are analyzed by means of micro-Raman spectroscopy. Measurements as a function of injection current demonstrate that the temperature at the laser output facet rises linearly with optical output power. Temperature profile measurements across the laser stripe show a strong correlation between near field intensity, facet temperature, and catastrophic optical damage (COD). Additionally, temperature-power analyses reveal that a critical facet temperature is needed to induce COD. The consistent results produced by complementary measurement techniques indicate that absorption of stimulated photons at the laser facet is the major source of facet heating. [ABSTRACT FROM AUTHOR]

The nanosecond dynamics of near-infrared semiconductor disk lasers is investigated experimentally and theoretically. Lasing and photoluminescence following barrier pumping are analyzed. Their spectral and temporal features such as luminescence overshoot and clamping, delay of lasing onset, and redshift of the emission are explained by a rate equation model taking into account the microscopic gain and luminescence. [ABSTRACT FROM AUTHOR]

The authors present a detailed investigation of defects generated during catastrophic optical damage (COD) in high-power 650 nm AlGaInP lasers using microphotoluminescence (μ-PL) mapping, focused ion beam (FIB) microscopy, and deep-etching techniques. High-resolution μ-PL images demonstrated that during COD, nonradiative dark line defects (DLDs) originate from the front mirror of the laser and propagate in several branches into the laser perpendicular to the output facet. Furthermore, FIB microscopy identified the epitaxial layers affected by COD, revealing that DLDs are confined to the active region. In addition, deep etching confirmed that these defects have a noncrystalline nature. [ABSTRACT FROM AUTHOR]

We describe the experimental cw power scaling of optically pumped semiconductor disk lasers OPS-DLs and give a detailed insight into the physical mechanism of this type of high-power surface-emitting semiconductor laser with external cavity. Minimizing the thermal resistance between active region and heat sink enables improved efficiency and gives access to high power and excellent beam quality of OPS-DL at 1000 nm. Results from initial numerical modeling are in good agreement with the experimental data, and show that thermal management is a critical parameter for the temperature-driven power shutoff in such devices. The computations are based on the macroscopic thermal transport, spatially resolved in both the radial and longitudinal directions, and coupled to the carrier density rate equations. A quantitative microscopic approach is used for the quantum-well gain and absorption dependence on wavelength, carrier density, and lattice temperature. The dependence of the computed output power on the substrate thickness and detuning are discussed. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We demonstrate more than 8-W continuous-wave output power with good beam quality (M² <1.8) from an optically pumped semiconductor disk laser. The combination of low threshold density of 470 W/cm² and high differential efficiency of 60% results in an optical-to-optical conversion efficiency of 46% for this high output level. Good epitaxial quality and low thermal resistance allow the scaling of output power with pump spot area. [ABSTRACT FROM AUTHOR]