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We experimentally demonstrate the control over the emission of quantum dots embedded in photonic molecules via mode field modulation. By locally changing the cavity frequencies we control, and even suppress, spontaneous emission.

We propose and theoretically investigate a new type of atom-phonon interaction in an optomechanical system. The interaction strength is controlled by the intensity of the intra-cavity optical field. We discuss relevant designs and possible applications.

Using a pump-probe differential transmission experiment in heterodyne detection, we measured the refractive index dynamics at the ground-state excitonic transition in electrically pumped InAs/GaAs quantum-dot amplifiers emitting near 1.3 µm at room temperature. We compare three samples differing only in the level of p-doping, and interpret the measured index changes taking into account the gain dynamics in these devices. We find that in absorption, the excess hole density due to p-doping accelerates the recovery and reduces the refractive index change, since filling of the hole states by p-doping shifts the induced changes in the hole population toward high energy states. Conversely, in gain, the reduced electron reservoir in the excited states in p-doped devices results in slower gain recovery dynamics and in larger refractive index changes compared to undoped devices operating at the same modal gain. The linewidth enhancement factor inferred from these measurements shows that p-doping is effective in reducing this parameter mainly due to the larger differential gain in p-doped devices in the gain regime. © 2009 IEEE.

Nanowire superconducting single photon detectors (SSPDs) are superior detectors of choice for many applications particularly in quantum information and communication technology. SSPD's excellent sensitivity and time resolution are brought about by the ultrafast transition of the very thin and narrow NbN nanowire meander from superconducting to normal state upon absorption of a single photon at near-infrared wavelengths [1]. However, low optical absorption in the ultrathin nanowire structures, puts a limit on the detection efficiency of these devices. A promising approach to improve the photon absorption in SSPDs is integrating them with advanced optical structures [2]. In this work, we report on the successful integration of SSPDs with optical cavity based on GaAs/AlAs distributed Bragg reflector (DBR) to enhance their detection efficiency.

Study of subwavelength optical phenomena has taken an increasing importance in the past few years. Near- field scanning optical microscopy (NSOM) is the usual solution for optical sensing below the diffraction limit. It consists in coupling light in a fiber through a nanoscale hole and detecting it with a conventional detector. A better optimized method would be to make the detector itself nanoscale. The dark count rate being usually proportional to the active area, this would greatly enhance the signal to noise ratio. The paper proposed a detector that has nanoscale dimensions, nanosecond response time and single or multiphoton sensitivity.

InAs quantum dots emitting at 1.3 Jµm and located inside a photonic crystal membrane nanocavity are studied by electrical pumping. An increase of the recombination rate is observed for quantum dots in resonance with the cavity mode.

Field-dependent photo-current measurements in Quantum Rod systems show that the orientation of the permanent dipole moment of a standard GaAs/InAs quantum dot can be reversed by fabricating high-aspect ratio Quantum Rod systems. ©2008 IEEE.

Date of Conference: 17-22 June 2007 The low voltage modulation in InAs quantum dot waveguides is observed in this paper. We have measured the electro-optic coefficient in multilayer quantum dot structures far away from resonance and obtained an enhancement compared to bulk GaAs. Electro-absorption measurement results suggest that these waveguides are good candidates for use in electro-absorption modulators such as Mach-Zehnder devices.