Coherent Acoustic Phonons in a Semiconductor Quantum Dot
نویسندگان
چکیده
Coherent acoustic phonons in PbS quantum dots are observed using femtosecond optical techniques. This is the first observation of coherent acoustic phonons in a semiconductor quantum dot; the phonons are generated through the deformation-potential coupling to the quantum-dot exciton. The acoustic modes are weakly damped, and we also find extremely weak coupling (S , 0.01) to the optical modes. These conclusions have important consequences for the vibronic nature of the exciton transition in the quantum dot and its dephasing. [S0031-9007(97)04822-9]
منابع مشابه
Direct evidence of interlevel exciton transitions mediated by single phonons in a semiconductor quantum dot using resonance fluorescence spectroscopy.
Using resonance fluorescence, we investigate how acoustic phonons mediate couplings between multiple electronic levels in a semiconductor quantum dot. We show the first direct evidence of population up-conversion in a single quantum dot, which we attribute to absorption of single acoustic phonons. Moreover, through a rate equation analysis, we find that below 20 K such single-phonon mediated co...
متن کاملDephasing processes in a single semiconductor quantum dot
We discuss the decoherence dynamics in a single semiconductor quantum dot and analyze two dephasing mechanisms. In the first part of the review, we examine the intrinsic source of dephasing provided by the coupling to acoustic phonons. We show that the non-perturbative reaction of the lattice to the interband optical transition results in a composite optical spectrum with a central zero-phonon ...
متن کاملEmission spectrum of a quantum dot embedded in a nanocavity
We model the emission spectrum of a quantum dot embedded in a (e.g. photonic crystal) nanocavity, using a semi-classical approach to describe the matter-field interaction. We start from the simple model of a quantum dot as a two-level system, and recover the result expected from cavity quantum electrodynamics. Then, we study the influence of electron-acoustic-phonons interaction. We show that t...
متن کاملControl of coherent acoustic phonons in semiconductor quantum wells.
Using subpicosecond optical pump-probe techniques, coherent zone-folded longitudinal acoustic phonons (ZFLAPs) were investigated in an InGaN multiple quantum well structure. A two-pump differential transmission technique was used to generate and control coherent ZFLAP oscillations through the relative timing and amplitude of the two pump pulses. Enhancement and suppression of ZFLAP oscillations...
متن کاملThe effect of the long-range order in a quantum dot array on the in-plane lattice thermal conductivity
Semiconductor quantum dot superlattices consisting of arrays of quantum dots have shown great promise for a variety of device applications, including thermoelectric power generation and cooling. In this paper we theoretically investigate the effect of long-range order in a quantum dot array on its in-plane lattice thermal conductivity. It is demonstrated that the long-range order in a quantum d...
متن کامل