研究目的
Investigating the optical characteristics of nonclassical light sources based on selectively positioned microlens structures and single (111) In(Ga)As quantum dots for developing single-photon emitters and photon-pair emitters entangled in polarization.
研究成果
The study demonstrated the single-photon character of radiation with g(2)(0) = 0.07 and investigated the fine structure of the exciton states of single (111) In(Ga)As QDs. It was shown that the splitting of the exciton states is comparable to the natural width of the exciton lines in the energy range of 1.320–1.345 eV, making these QDs promising for creating photon-pair emitters entangled in polarization.
研究不足
The study is limited by the technical constraints of the experimental setup and the specific characteristics of the quantum dots and microlens structures used. Potential areas for optimization include improving the external quantum efficiency of the emitters and further reducing the splitting of exciton states.
1：Experimental Design and Method Selection:
The study involved the fabrication of microcavities consisting of a semiconductor Bragg reflector and a microlens selectively positioned above a single (111) In(Ga)As quantum dot. The optical characteristics were investigated using cryogenic micro-photoluminescence technique and the radiation statistics was analyzed using a Hanbury Brown–Twiss interferometer.
2：Sample Selection and Data Sources:
The initial structure was grown using molecular-beam epitaxy (MBE) and consisted of a semiconductor distributed Bragg reflector (DBR) and a GaAs layer containing a (111) InGaAs QD layer.
3：List of Experimental Equipment and Materials:
A tunable Ti:Al2O3 laser, a triVista-555 triple monochromator with a cooled array of Si photodetectors, and photon counters based on Si avalanche photodiodes 'PerkinElmer SPCM-AQRH-15' were used.
4：Experimental Procedures and Operational Workflow:
The luminescence spectra were measured, and the radiation statistics was analyzed based on measuring the pair-photon correlations. The splitting parameter Δ EFS of the exciton states was determined from the polarization measurements.
5：Data Analysis Methods:
The spectral position of the luminescence peaks was determined by approximating the experimental microluminescence spectra by Lorentzian contours.
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