Semiconductor nanostructures for flying q-bits and green photonics

Abstract

Breakthroughs in nanomaterials and nanoscience enable the development of novel photonic devices and systems ranging from the automotive sector, quantum cryptography to metropolitan area and access networks. Geometrical architecture presents a design parameter of device properties. Self-organization at surfaces in strained heterostructures drives the formation of quantum dots (QDs). Embedding QDs in photonic and electronic devices enables novel functionalities, advanced energy efficient communication, cyber security, or lighting systems. The recombination of excitons shows twofold degeneracy and Lorentzian broadening. The superposition of millions of excitonic recombinations from QDs in real devices leads to a Gaussian envelope. The material gain of QDs in lasers is orders of magnitude larger than that of bulk material and decoupled from the index of refraction, controlled by the properties of the carrier reservoir, thus enabling independent gain and index modulation. The threshold current density of QD lasers is lowest of all injection lasers, is less sensitive to defect generation, and does not depend on temperature below 80°C. QD lasers are hardly sensitive to back reflections and exhibit no filamentation. The recombination from single QDs inserted in light emitting diodes with current confining oxide apertures shows polarized single photons. Emission of ps pulses and date rates of 10 10 + bit upon direct modulation benefits from gain recovery within femtoseconds. Repetition rates of several 100 GHz were demonstrated upon mode-locking. Passively mode-locked QD lasers generate hat-like frequency combs, enabling Terabit data transmission. QD-based semiconductor optical amplifiers enable multi-wavelength amplification and switching and support multiple modulation formats.Keywords: quantum dot growth and electronic properties; quantum dot lasers; ultra-fast lasers and amplifiers; single q-bit emitters.

InAs/AlGaAs quantum dots for single-photon emission in a red spectral range

“…Self-organized single quantum dots (QDs) grown by epitaxial techniques are promising candidates for creation of the single-photon sources, because of their small emission linewidth, fast radiative decay time, high and stable quantum efficiency, and ability to be integrated with electronic devices 8 . Strain-induced QDs from a variety of different material systems, grown by the Stranski-Krastanov method, have been studied spectroscopically on a single QD level 9 , 10 , including InAs/GaAs, InP/(Al,Ga,In)P, CdSe/Zn(S)Se, CdTe/ZnTe, and more recently (In,Ga)N/(Al,Ga)N 11 , 12 , InAs/InAlGaAsP 13 – 15 , and InAs/InGaAs 16 – 18 . All together, these systems allow fabrication of the single-photon emitters in an extended spectral range from middle ultraviolet to the optical telecommunication C-band (1.55 μ m).…”

Light Absorption Enhancement and Laser-Induced Damage Ability Improvement of Aluminum Alloy 6061 with Non-Porous Alumina/CdSe@Al2O3/SiO2 Functional Gradient Films

“…Semiconductor nanocrystals (SNCs) such as cadmium selenide (CdSe) quantum dots offer wide applications in the fields of photovoltaics, solar energy harvesting, nanophotonics, imaging, sensing and other fields [ 20 , 21 , 22 , 23 , 24 , 25 ]. Since incident radiation causes excitation of free electrons, metal nanoparticles (MNPs) can generate intense electric fields in their vicinity [ 26 ].…”

Light Absorption Enhancement and Laser-Induced Damage Ability Improvement of AA 6061 with Non-porous Alumina /CdSe@Al₂O₃/SiO₂ Functional Gradient Films

“…Semiconductor nanocrystals (SNCs) like cadmium selenide (CdSe) quantum dots offer widely application in the field of photovoltaics, solar energy harvesting, nanophotonics, imaging, sensing and other fields [17][18][19][20][21][22]. Since incident radiation excitation of free electrons, metal nanoparticles (MNPs) can generate intense electric fields in their vicinity [23].…”