Modeling of an efficient singlet-triplet spin qubit to photon interface assisted by a photonic crystal cavity

arXiv (Cornell University)

Abstract

Efficient interconnection between distant semiconductor spin qubits with the help of photonic qubits would offer exciting new prospects for future quantum communication applications. In this paper, we optimize the extraction efficiency of a novel interface between a singlet-triplet spin qubit and a photonic qubit. The interface is based on a 220 nm thick GaAs/AlGaAs heterostructure membrane and consists of a gate-defined double quantum dot (GDQD) supporting a singlet-triplet qubit, an optically active quantum dot (OAQD) consisting of a gate-defined exciton trap, a photonic crystal cavity providing in-plane optical confinement and efficient out-coupling to an ideal free space Gaussian beam while accommodating the gate wiring of the GDQD and OAQD, and a bottom gold reflector to recycle photons and increase the optical extraction efficiency. All essential components can be lithographically defined and deterministically fabricated on the GaAs/AlGaAs heterostructure membrane, which greatly increases the scalability of on-chip integration. According to our simulations, the interface provides an overall coupling efficiency of 28.7% into a free space Gaussian beam, assuming an SiO2 interlayer filling the space between the reflector and the membrane. The performance can be further increased by undercutting this SiO2 interlayer below the photonic crystal. In this case, the overall efficiency is calculated to be 48.5%.

Authors 9

1. Kui Wu Aachen nd Institute of Physics

   RWTH Aachen University

   Affiliation as printed

   nd Institute of Physics , RWTH Aachen University , Aachen , 52074 , Germany

2. Sebastian Kindel
   Affiliation as printed

   Quantum Technology Group ,

3. Thomas Descamps
   Affiliation as printed

   Quantum Technology Group ,

4. Tobias Hangleiter
   Affiliation as printed

   Quantum Technology Group ,

5. Jan Christoph Müller
6. Rebecca Rodrigo Aachen Institute of Integrated Photonics (IPH)

   RWTH Aachen University

   Affiliation as printed

   Institute of Integrated Photonics , RWTH Aachen University , Aachen , 52074 , Germany

7. Florian Merget Aachen Institute of Integrated Photonics (IPH)

   RWTH Aachen University

   Affiliation as printed

   Institute of Integrated Photonics , RWTH Aachen University , Aachen , 52074 , Germany

8. Hendrik Bluhm
   Affiliation as printed

   Quantum Technology Group ,

9. Jeremy Witzens Aachen Institute of Integrated Photonics (IPH)

   RWTH Aachen University

   Affiliation as printed

   Institute of Integrated Photonics , RWTH Aachen University , Aachen , 52074 , Germany