Conversion of Single Microwave Photons to Optical Photons Using Rare-Earth-Doped Crystals
Abstract
The goal of this project is to convert single microwave photons generated on superconducting chips to single optical photons. The single microwave photons are produced using superconducting Josephson junction qubits coupled to superconducting resonators. The conversion process is mediated by an ensemble of rare earth ions (REIs) doped in a crystal that is coupled simultaneously with high cooperativity to both the superconducting resonator and an optical resonator. Our team members have already demonstrated measurable transduction of microwave photons to optical photons using REIs coupled to macroscopic resonators (co-Pl Longdell), integration of REIs with on-chip photonic and microwave devices for quantum memory and quantum transduction (PI Faraon), and devices integrating superconducting qubits and resonators (Co-PI Schwab). In this project, we will merge our expertise to demonstrate on-chip microwave to optical conversion at the single photon level. This proposal addresses mainly topic II.A.2.a CQTS: Quantum-state-transfer from microwave to optical wavelengths, but is also highly relevant to topic II.A.2.b CQTS: Classical, highly efficient, microwave to optical conversion. The experimental work is divided in two interconnected thrusts. In Thrust I we will design, fabricate and measure on-chip devices that integrate photonic resonators, microwave resonators and superconducting qubits, with REI- doped crystals. The device will be designed and built using the tools already developed for silicon photonics, one of the most mature technologies for on-chip photonics. Single photons generated using superconducting qubits in the microwave regime will be converted to optical photons. The end technical goal is to demonstrate single photon statistics (i.e. anti-bunching) in the optical domain only using the superconducting device and microwave-to-optical transduction. The indistinguishability of the transduced photons will be measured and the fidelity of the transduction process will be characterized. The impact of the optical transduction device on the coherence of the superconducting qubit and the superconducting resonator will be measured. Techniques for minimizing the degradation of the superconducting circuitry due to spurious optical photons will be investigated. In Thrust II we will continue improving the efficiency of the macroscopic conversion device already demonstrated. The macroscopic device will serve as a test-bed for confirming the predicted efficiency and fidelity of the quantum transduction process and studying its noise sources. The main factor for improving efficiency is cooling the device below 1K. Towards this end we will build a more compact fiber-coupled setup that will be measured at dilution refrigerator temperatures. High extinction optical filtering techniques based on other REI-doped crystals and Fabry-Perot etalons will be developed. These filters will also be used to filter the signal for the on-chip device developed in Thrust I. Noise sources will be analyzed and minimized. Optical properties of isotopically pure REI-doped crystals will be measured. The knowledge acquired in Thrust II will be used for the on-chip transduction device developed in Thrust I, and vice-versa.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2018
- Source ID
- W911NF1810011
Entities
People
- Andrei Faraon
Organizations
- Army Contracting Command
- California Institute of Technology
- National Security Agency