# US 11,440,792 B2 · Techniques for bidirectional transduction of quantum level signals between optical and microwave frequencies using a common acoustic intermediary > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,440,792 B2 - Document ID: US11440792B2 - Status: Granted - Kind: B2 - Application number: 17/087,400 - Filed: 2020-11-02 - Published: 2021-04-22 - Granted: 2022-09-13 - Earliest claimed: 2018-03-05 - Assignees: California Institute of Technology - Applicants: California Institute of Technology - Inventors: Oskar Painter; Jie Luo; Michael T. Fang; Alp Sipahigil; Paul B. Dieterle; Mahmoud Kalaee; Johannes M. Fink; Andrew J. Keller; Gregory MacCabe; Hengjiang Ren; Justin D. Cohen - Web page: https://patentgrep.com/patent/US11440792B2 ## CPC - B81B 3/0029: {Transducers for transforming light into mechanical energy or viceversa} - G11C 13/04: using optical elements {; using other beam accessed elements, e.g. electron or ion beam} - B81B 3/0021: {Transducers for transforming electrical into mechanical energy or vice versa (dynamo-electric machines H02K99/00; electrostatic machines H02N1/00; piezoelectric devices H10N30/00)} - B82Y 10/00: Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic - B82Y 20/00: Nanooptics, e.g. quantum optics or photonic crystals - B82Y 40/00: Manufacture or treatment of nanostructures - G01H 11/08: using piezoelectric devices - G06N 10/40: Physical realisations or architectures of quantum processors or components for manipulating qubits, e.g. qubit coupling or qubit control - G11C 13/025: {using fullerenes, e.g. C60, or nanotubes, e.g. carbon or silicon nanotubes} - G11C 13/048: {using other optical storage elements} - H10D 48/3835: {Semiconductor qubit devices comprising a plurality of quantum mechanically interacting semiconductor quantum dots, e.g. Loss-DiVincenzo spin qubits} - B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00) - G11C: STATIC STORES (semiconductor memory devices H10B) - B82Y: SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES - G06N: COMPUTING ARRANGEMENTS BASED ON SPECIFIC COMPUTATIONAL MODELS - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES ## Abstract Embodiments described herein include systems and techniques for converting (i.e., transducing) a quantum-level (e.g., single photon) signal between the three wave forms (i.e., optical, acoustic, and microwave). A suspended crystalline structure is used at the nanometer scale to accomplish the desired behavior of the system as described in detail herein. Transducers that use a common acoustic intermediary transform optical signals to acoustic signals and vice versa as well as microwave signals to acoustic signals and vice versa. Other embodiments described herein include systems and techniques for storing a qubit in phonon memory having an extended coherence time. A suspended crystalline structure with specific geometric design is used at the nanometer scale to accomplish the desired behavior of the system. ## Claims ### Claim 1 A method for transducing a quantum signal, the method comprising: receiving, by a suspended crystalline optical waveguide, a quantum optical signal from an optical device; converting, by a first suspended crystalline transducer, the quantum optical signal propagating through the suspended crystalline optical waveguide to a quantum acoustic signal, wherein the first suspended crystalline transducer oscillates at a tuning frequency during the converting; tuning a second suspended crystalline transducer to oscillate at the tuning frequency; in response to the tuning, converting, by the second suspended crystalline transducer, the quantum acoustic signal to a quantum microwave signal; and transmitting the quantum microwave signal on a conductor. ### Claim 2 (depends on 1) The method for transducing the quantum signal of claim 1, wherein the suspended crystalline optical waveguide is surrounded by a plurality of suspended crystalline structures disposed in a geometric design to isolate the quantum optical signal outside of the suspended crystalline optical waveguide. ### Claim 3 (depends on 1) The method for transducing the quantum signal of claim 1, wherein the second suspended crystalline transducer comprises a piezoelectric material overlay of a suspended crystalline structure. ### Claim 4 (depends on 3) The method for transducing the quantum signal of claim 3, wherein the piezoelectric material comprises Aluminum Nitride. ### Claim 5 (depends on 3) The method for transducing the quantum signal of claim 3, further comprising: providing alternating polarity electrical signals via a plurality of conductors that are electrically coupled in an interleaved pattern to the piezoelectric material overlay of the suspended crystalline structure to generate an oscillation at the tuning frequency. ### Claim 6 (depends on 1) The method for transducing the quantum signal of claim 1, wherein: the second suspended crystalline transducer comprises a suspended crystalline structure and a plurality of conductors overlaying the suspended crystalline structure; the plurality of conductors are configured to form a plurality of capacitive features; during transduction, the plurality of capacitive features oscillate at the tuning frequency to generate a changing capacitance; and the quantum microwave signal is generated based on the changing capacitance. ### Claim 7 (depends on 1) The method for transducing the quantum signal of claim 1, wherein the suspended crystalline optical waveguide, the first suspended crystalline transducer, and the second suspended crystalline transducer each comprise silicon. ### Claim 8 (depends on 1) The method for transducing the quantum signal of claim 1, wherein the conductor comprises aluminum.