arXiv subjects

Hidekazu Kumano

Publications and source records attributed to Hidekazu Kumano.

3 recordsLinked to original sources

arXiv2017

Fiber-coupled pillar array as a highly pure and stable single-photon source

A highly pure and stable single-photon source is prepared that comprises a well-designed pillar array in which each pillar contains only a few InAs quantum dots. A nano-pillar in this array is in direct contact with a fiber end surface and cooled in a liquid-He bath. Auto-correlation measurement shows that this source provides an average $g^{(2)}(0)$ value of 0.0174 in the measured excitation-power range. This photon source and fiber coupling are quite rigid against external disturbances such as cooling-heating cycles and vibration, with long-term stability.

cond-mat.mes-hall↗

arXiv2012

Anomalous dip observed in intensity autocorrelation function as an inherent nature of single-photon emitters

We report the observation of an anomalous antibunching dip in intensity autocorrelation function with photon correlation measurements on a single-photon emitter (SPE). We show that the anomalous dip observed is a manifestation of quantum nature of SPEs. Taking population dynamics in a quantum two-level system into account correctly, we redefine intensity autocorrelation function. This is of primary importance for precisely evaluating the lowest-level probability of multiphoton generation in SPEs toward realizing versatile pure SPEs for quantum information and communication.

cond-mat.mes-hall↗

arXiv2012

Telecommunication band InAs quantum dots and dashes embedded in different barrier materials

We investigate the long wavelength (1.2 to 1.55 micro-m) photoluminescence of high-density InAs quantum dots and dashes, which were grown on InP substrates. We analyze the temperature dependence of the recombination and carrier distribution on the alloy composition of the barrier materials, InGaAlAs, and on the existence of a wetting layer. Carrier escape and transfer are discussed based on temperature dependent photoluminescence measurements and theoretical considerations about the heterostructures' confinement energies and band structure. We propose two different contributions to the thermal quenching, which can explain the observations for both the quantum dot and dash samples. Among these one is a unique phenomenon for high density quantum dot/dash ensembles which is related to significant inter-dot/dash coupling. With the goal ahead to use these dots and dashes for quantum optical applications on the single-dot/dash level in the telecommunication C band as well as at elevated temperatures we present first steps towards the realization of such devices.

cond-mat.mes-hall↗