“…The InGaAsP layers are lattice matching to the InP substrate and have an energy gap larger than the photon energy of 1.3-μm wavelength, so that they are extremely transparent for ~1.55-μm light. Compared to the previous air-gap DBR cavities [ 13 , 17 , 18 ], in which non-air-gap regions are imperfect features or mechanical supporters, the remaining semiconductor in the partial air-gap layers here takes both the mechanically supporting and optically confining roles so that the present cavity appears completely free standing. Fig.…”
Section: Methodsmentioning
confidence: 87%
“…This thickness is actually a quarter wavelength of air because the optical media of this layer in the pillar is mainly air rather than InP. In the case of planar air-gap DBR cavities [ 13 , 17 , 18 ], semiconductor layers are usually set to be three-quarter-wavelength thick, but our simulation implies that this design in our case hardly has good cavity quality. Thus, the InGaAsP layers in the DBRs are set quarter-wavelength thick, i.e., t 2 = λ B /(4 n 2 ), where n 2 is the refractive index of InGaAsP.…”
Section: Methodsmentioning
confidence: 99%
“…In the case of planar DBR cavity, an effective way to increase refractive index contrast of InP-based materials is to introduce air gaps by sacrificing some semiconductor layers [ 13 , 17 ]. For pillar cavities, partial air-gap layers like in GaAs/air DBR cavities [ 18 ] might be incorporated to enhance the refractive index contrast. In this work, therefore, we propose a nanopillar cavity consisting of InGaAsP/InP layers with partial air gaps, which can be monolithically fabricated.…”
A new structure of 1.55-μm pillar cavity is proposed. Consisting of InP-air-aperture and InGaAsP layers, this cavity can be fabricated by using a monolithic process, which was difficult for previous 1.55-μm pillar cavities. Owing to the air apertures and tapered distributed Bragg reflectors, such a pillar cavity with nanometer-scaled diameters can give a quality factor of 104–105 at 1.55 μm. Capable of weakly and strongly coupling a single quantum dot with an optical mode, this nanocavity could be a prospective candidate for quantum-dot single-photon sources at 1.55-μm telecommunication band.
“…The InGaAsP layers are lattice matching to the InP substrate and have an energy gap larger than the photon energy of 1.3-μm wavelength, so that they are extremely transparent for ~1.55-μm light. Compared to the previous air-gap DBR cavities [ 13 , 17 , 18 ], in which non-air-gap regions are imperfect features or mechanical supporters, the remaining semiconductor in the partial air-gap layers here takes both the mechanically supporting and optically confining roles so that the present cavity appears completely free standing. Fig.…”
Section: Methodsmentioning
confidence: 87%
“…This thickness is actually a quarter wavelength of air because the optical media of this layer in the pillar is mainly air rather than InP. In the case of planar air-gap DBR cavities [ 13 , 17 , 18 ], semiconductor layers are usually set to be three-quarter-wavelength thick, but our simulation implies that this design in our case hardly has good cavity quality. Thus, the InGaAsP layers in the DBRs are set quarter-wavelength thick, i.e., t 2 = λ B /(4 n 2 ), where n 2 is the refractive index of InGaAsP.…”
Section: Methodsmentioning
confidence: 99%
“…In the case of planar DBR cavity, an effective way to increase refractive index contrast of InP-based materials is to introduce air gaps by sacrificing some semiconductor layers [ 13 , 17 ]. For pillar cavities, partial air-gap layers like in GaAs/air DBR cavities [ 18 ] might be incorporated to enhance the refractive index contrast. In this work, therefore, we propose a nanopillar cavity consisting of InGaAsP/InP layers with partial air gaps, which can be monolithically fabricated.…”
A new structure of 1.55-μm pillar cavity is proposed. Consisting of InP-air-aperture and InGaAsP layers, this cavity can be fabricated by using a monolithic process, which was difficult for previous 1.55-μm pillar cavities. Owing to the air apertures and tapered distributed Bragg reflectors, such a pillar cavity with nanometer-scaled diameters can give a quality factor of 104–105 at 1.55 μm. Capable of weakly and strongly coupling a single quantum dot with an optical mode, this nanocavity could be a prospective candidate for quantum-dot single-photon sources at 1.55-μm telecommunication band.
“…It attracts plenty of attention due to its high tunability and extensibility, which can be enhanced by introducing additional structures, for example, defects and gratings. The most important applications of the DBR are optical switches 10 11 , lasers 12 13 14 , sensors 15 , couplers 3 , and narrow-band filters 2 4 16 . Narrow-band filters can be realized by a semiconductor microcavity that consists of two DBRs and one cavity layer 17 18 .…”
The transmission behaviour of a distributed Bragg reector (DBR) with surface dielectric gratings on top and bottom is studied. The transmission shows a comb-like spectrum in the DBR band gap, which is explained in the Fano picture. The number density of the transmission peaks increases with increasing number of cells of the DBR, while the ratio of the average full width at half maximum to the corresponding average free spectral range, being only few percent for both transversal electric and magnetic waves, is almost invariant. The transmission peaks can be narrower than 0.1 nm and are fully separated from each other in certain wavebands. We further prove that the transmission combs are robust against randomness in the heights of the DBR layers. Therefore, the proposed structure is a candidate for an ultra-narrow-band multichannel filter or polarizer.
We compare alternative planar cavity structures for strong exciton-photon coupling, where the conventional distributed Bragg reflector (DBR) and three unconventional types of cavity mirrors -air/GaAs DBR, Tamm-plasmon mirror and sub-wavelength grating mirror. We design and optimize the planar cavities built with each type of mirror at one side or both sides for maximum vacuum field strength. We discuss the trade-off between performance and fabrication difficulty for each cavity structure. We show that cavities with sub-wavelength grating mirrors allow simultaneously strongest field and high cavity quality. The optimization principles and techniques developed in this work will guide the cavity design for research and applications of matter-light coupled semiconductors, especially new material systems that require greater flexibility in the choice of cavity materials and cavity fabrication procedures.
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