We study the optical amplification and absorption properties in a double-Λ four level system of GaAs/AlGaAs multiple quantum wells(MQWs) under realistic experimental conditions.The amplification and absorption responses of two weak fields can be achieved by adjusting the relative phase,the probe detuning,and the two pump Rabi frequencies appropriately.The investigation is much more practical than its atomic counterpart because of its flexible design and the wide adjustable parameters.It may provide a new possibility in technological applications for the light amplifier working on quantum coherence effects in MQWs solid-state system.
We demonstrate the slow light in double quantum dots (QDs) resonance dispersion material in theory. The slow factor, absorption, and bandwidth are greatly influenced by the energy difference of the two resonance energy. The bandwidth of this system is up to 60 GHz. The 20 ps input signal pulse is delayed by 180 ps (group index of approximately 55) relative to free-space propagation with little broadening in 1 mm dispersion material for the optical communication wavelength. The signal pulse delay can be tuned by the pump pulse.
All-optical switch with the ultrafast optical switching rate is a key device in the next generation optical network.In this article,we propose a polarization switch with ps switching time,which is constructed from one-dimensional resonant photonic crystal(1D RPC).The model of switch operating at 1.5 μm is established based on the optical stark effect(OSE).We calculate the performance indices of the switch and the influences of errors of periods and refractive index on the performance characteristics.
The effects of polarization and related structural parameters on the intersubband transitions of AlGaN/GaN multiquantum wells (MQWs) have been investigated by solving the Schrdinger and the Poisson equations self-consistently. The results show that the intersubband absorption coefficient increases with increasing polarization while the transition wavelength decreases, which is not identical to the case of the interband transitions. Moreover, it suggests that the well width has a greater effect on the intersubband transitions than the barrier thickness, and the intersubband transition wavelength of the structure when doped in the barrier is shorter than that when doped in the well. It is found that the influences of the structural parameters differ for different electron subbands. The mechanisms responsible for these effects have been investigated in detail.
