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Resonance-enhanced spontaneous emission originating from quantum dots was investigated. The results showed that when the radius of the sphere was small as compared to the wavelength of emitted light, the spontaneous emission rate decreased by a factor of 80. However, when the radius was comparable to the wavelength, the radius determined the rate of spontaneous emmision. In addition, sharp resonances related to Mie resonances were observed.

Injection locking of a radiation-pressure optomechanical oscillator is demonstrated through external modulation of the optical pump power near the optomechanical oscillation frequency. It is shown that the frequency and phase of a microtoroidal optomechanical oscillator can be locked to those of an electronic oscillator (or any other signal) that can modulate the optical input power and whose frequency is within the lock range. [ABSTRACT FROM AUTHOR]

Detuned operation of a laser results in coupling of field amplitude and phase fluctuations. In a semiconductor laser, this coupling is known to be very large. We demonstrate that it can be used to significantly reduce intensity noise below its intrinsic limit. [ABSTRACT FROM AUTHOR]

We use the active-layer photomixing technique to directly modulate the output of a GaAs semiconductor laser operating at temperatures as low as 4.2 K. The technique produces modulation with nearly perfect immunity to device parasitic effects, revealing the laser diode’s intrinsic modulation response. At 4.2 K the parasitic corner frequency is estimated to be 410 MHz, yet the response appears ideal out to 15 GHz. We measure the dynamical parameters governing the response function, the relaxation resonance frequency, and the damping rate, and discuss their low-temperature behavior. [ABSTRACT FROM AUTHOR]

The maximum optical gain and the spontaneous noise enhancement factor in quantum well structures are expressed as extremely simple functions that are accurate over a wide range of carrier densities. These expressions are used to study the effect of doping on the optical gain and the noise enhancement factor in a 100 Å InGaAs/InP quantum well structure. n-type doping is most effective in reducing the transparency excitation level (laser threshold) and the noise enhancement factor (amplifier noise figure), whereas p-type doping enables increased gain at a given excitation level. [ABSTRACT FROM AUTHOR]

The selective growth of nanometer scale GaAs wire and dot structures using metalorganic vapor phase epitaxy is demonstrated. Spectrally resolved cathodoluminescence images as well as spectra from single dots and wires are presented. A blue shifting of the GaAs peak is observed as the size scale of the wires and dots decreases. [ABSTRACT FROM AUTHOR]

We report the first observation of a lateral junction formed in an alloy due to an abrupt transition from segregated to random AlGaAs alloy compositions. Al0.25Ga0.75As epilayers were grown by molecular beam epitaxy on [011] oriented grooves in a nonplanar (100) GaAs substrate. A quasi-periodic modulation of the aluminum concentration occurs spontaneously in material grown on the (111) facets of the groove, with a period of 50–70 Å along the [111] direction. The compositional modulation is associated with a reduction of the band gap by 130 meV, with respect to the random alloy. While segregation of the AlGaAs alloy has been seen previously, this is the first observation of segregation of AlGaAs grown on a (111) surface. The compositional modulation terminates abruptly at the boundaries of the (111) facet, forming abrupt lateral junctions in the AlGaAs layers grown on a groove. [ABSTRACT FROM AUTHOR]