Abstract

We report an easy-to-fabricate microcavity design to produce optically pumped high-β quantum dot microlasers. Our cavity concept is based on a buried photonic-defect for tight lateral mode confinement in a quasi-planar microcavity system, which includes an upper dielectric distributed Bragg reflector (DBR) as a promising alternative to conventional III-V semiconductor DBRs. Through the integration of a photonic-defect, we achieve low mode volumes as low as 0.28 µm3, leading to enhanced light-matter interaction, without the additional need for complex lateral nanoprocessing of micropillars. We fabricate semiconductor-dielectric hybrid microcavities, consisting of Al0.9Ga0.1As/GaAs bottom DBR with 33.5 mirror pairs, dielectric SiO₂/SiNx top DBR with 5, 10, 15, and 19 mirror pairs, and photonic-defects with varying lateral size in the range of 1.5 µm to 2.5 µm incorporated into a one-λ/n GaAs cavity with InGaAs quantum dots as active medium. The cavities show distinct emission features with a characteristic photonic defect size-dependent mode separation and Q-factors up to 17000 for 19 upper mirror pairs in excellent agreement with numeric simulations. Comprehensive investigations further reveal lasing operation with a systematic increase (decrease) of the β-factor (threshold pump power) with the number of mirror pairs in the upper dielectric DBR. Notably, due to the quasi-planar device geometry, the microlasers show high temperature stability, evidenced by the absence of temperature-induced red-shift of emission energy and linewidth broadening typically observed for nano- and microlasers at high excitation powers.

Abstract

We report an easy-to-fabricate microcavity design to produce optically pumped high-β quantum dot microlasers. Our cavity concept is based on a buried photonic-defect for tight lateral mode confinement in a quasi-planar microcavity system, which includes an upper dielectric distributed Bragg reflector (DBR) as a promising alternative to conventional III-V semiconductor DBRs. Through the integration of a photonic-defect, we achieve low mode volumes as low as 0.28 µm3, leading to enhanced light-matter interaction, without the additional need for complex lateral nanoprocessing of micropillars. We fabricate semiconductor-dielectric hybrid microcavities, consisting of Al0.9Ga0.1As/GaAs bottom DBR with 33.5 mirror pairs, dielectric SiO₂/SiNx top DBR with 5, 10, 15, and 19 mirror pairs, and photonic-defects with varying lateral size in the range of 1.5 µm to 2.5 µm incorporated into a one-λ/n GaAs cavity with InGaAs quantum dots as active medium. The cavities show distinct emission features with a characteristic photonic defect size-dependent mode separation and Q-factors up to 17000 for 19 upper mirror pairs in excellent agreement with numeric simulations. Comprehensive investigations further reveal lasing operation with a systematic increase (decrease) of the β-factor (threshold pump power) with the number of mirror pairs in the upper dielectric DBR. Notably, due to the quasi-planar device geometry, the microlasers show high temperature stability, evidenced by the absence of temperature-induced red-shift of emission energy and linewidth broadening typically observed for nano- and microlasers at high excitation powers.

Abstract

We report an easy-to-fabricate microcavity design to produce optically pumped high-β quantum dot microlasers. Our cavity concept is based on a buried photonic-defect for tight lateral mode confinement in a quasi-planar microcavity system, which includes an upper dielectric distributed Bragg reflector (DBR) as a promising alternative to conventional III-V semiconductor DBRs. Through the integration of a photonic-defect, we achieve low mode volumes as low as 0.28 µm3, leading to enhanced light-matter interaction, without the additional need for complex lateral nanoprocessing of micropillars. We fabricate semiconductor-dielectric hybrid microcavities, consisting of Al0.9Ga0.1As/GaAs bottom DBR with 33.5 mirror pairs, dielectric SiO₂/SiNx top DBR with 5, 10, 15, and 19 mirror pairs, and photonic-defects with varying lateral size in the range of 1.5 µm to 2.5 µm incorporated into a one-λ/n GaAs cavity with InGaAs quantum dots as active medium. The cavities show distinct emission features with a characteristic photonic defect size-dependent mode separation and Q-factors up to 17000 for 19 upper mirror pairs in excellent agreement with numeric simulations. Comprehensive investigations further reveal lasing operation with a systematic increase (decrease) of the β-factor (threshold pump power) with the number of mirror pairs in the upper dielectric DBR. Notably, due to the quasi-planar device geometry, the microlasers show high temperature stability, evidenced by the absence of temperature-induced red-shift of emission energy and linewidth broadening typically observed for nano- and microlasers at high excitation powers.

Abstract

We report an easy-to-fabricate microcavity design to produce optically pumped high-β quantum dot microlasers. Our cavity concept is based on a buried photonic-defect for tight lateral mode confinement in a quasi-planar microcavity system, which includes an upper dielectric distributed Bragg reflector (DBR) as a promising alternative to conventional III-V semiconductor DBRs. Through the integration of a photonic-defect, we achieve low mode volumes as low as 0.28 µm3, leading to enhanced light-matter interaction, without the additional need for complex lateral nanoprocessing of micropillars. We fabricate semiconductor-dielectric hybrid microcavities, consisting of Al0.9Ga0.1As/GaAs bottom DBR with 33.5 mirror pairs, dielectric SiO₂/SiNx top DBR with 5, 10, 15, and 19 mirror pairs, and photonic-defects with varying lateral size in the range of 1.5 µm to 2.5 µm incorporated into a one-λ/n GaAs cavity with InGaAs quantum dots as active medium. The cavities show distinct emission features with a characteristic photonic defect size-dependent mode separation and Q-factors up to 17000 for 19 upper mirror pairs in excellent agreement with numeric simulations. Comprehensive investigations further reveal lasing operation with a systematic increase (decrease) of the β-factor (threshold pump power) with the number of mirror pairs in the upper dielectric DBR. Notably, due to the quasi-planar device geometry, the microlasers show high temperature stability, evidenced by the absence of temperature-induced red-shift of emission energy and linewidth broadening typically observed for nano- and microlasers at high excitation powers.