Qubit Laser Annealing With Diffractive Beam Splitting
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Solution Overview
Problem
Laser annealing techniques for qubits face challenges due to microscale size and design constraints, requiring precise optical alignment that is difficult to achieve, and can damage superconducting leads if misaligned.
Innovation Solution
The use of a diffractive beam splitter to split a single optical beam into multiple Gaussian beams, which are projected onto the substrate around the Josephson junction, avoiding direct irradiation and allowing for uniform heating without precise alignment, thus minimizing damage and achieving consistent annealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single optical beam is used for laser annealing, then the annealing process is simple, but precise optical alignment is difficult to achieve and damage to superconducting leads occurs
Solution Approach 1:
The single optical beam is segmented into multiple beams (e.g., four beams) that are spatially separated and directed at different regions surrounding the Josephson junction. This segmentation allows each beam to be independently positioned, eliminating the need for precise alignment of a single beam while distributing the thermal load to avoid damage to superconducting leads.
Solution Approach 2:
The patent introduces an intermediary optical element (such as a diffractive optical element or beam splitter) that transforms the single beam into multiple beams. This intermediary component facilitates the transition from a single-beam configuration requiring precise alignment to a multi-beam configuration with relaxed alignment requirements, while effectively delivering thermal energy to the target region.
2Stability of the object's composition
If multiple optical beams are used for annealing, then uniform heating is achieved, but the device complexity increases
Solution Approach 1:
The patent employs a universal optical component (such as a diffractive optical element or beam splitter) that simultaneously performs multiple functions: dividing the single beam into multiple beams, spatially separating the beams, and directing them toward the target region. This multi-functional component achieves uniform heating without requiring multiple separate optical systems, thereby limiting the increase in device complexity.
Solution Approach 2:
The patent changes the spatial distribution parameter of the optical beams by transforming a single concentrated beam into multiple spatially separated beams. This parameter change enables uniform temperature distribution across the target region while the use of standard optical components keeps the overall system complexity manageable.
3Productivity
If direct laser irradiation is applied to the Josephson junction, then annealing efficiency is high, but the risk of damage increases
Solution Approach 1:
Instead of directly irradiating the Josephson junction with the optical beam, the patent inverts the approach by directing multiple beams at regions surrounding the junction. The thermal energy diffuses from these surrounding regions into the junction, achieving annealing while avoiding direct laser-matter interaction that could cause damage.
Solution Approach 2:
The patent converts the potential harm of direct laser irradiation into a beneficial indirect heating mechanism. By positioning beams to illuminate regions adjacent to the Josephson junction, the thermal diffusion process becomes the useful mechanism for annealing, while the avoidance of direct irradiation prevents localized overheating and damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively adjusts the qubit's resonant frequency by indirectly heating the Josephson junction, reducing the risk of damage and ensuring uniform temperature distribution, even with minor laser misalignment, thereby improving qubit frequency control in quantum computing.
Implementation Method 1
generating the Gaussian beams via transmission of a laser generated Gaussian beam through a diffractive optical element
Implementation Method 2
The plurality of optical beams indirectly heat the Josephson junction, resulting in the annealing of the Josephson junction
Data Source
AI summary
Apparatuses and methods are described for laser annealing of a qubit device using a plurality of optical beams. According to an embodiment, a method of tuning a qubit device can comprise generating an optical beam, splitting the optical beam in a plurality of optical beams, and annealing a Josephson junction of the qubit device by projecting the plurality of optical beams onto a region of the qubit device adjacent to the Josephson junction. The disclosed techniques can also be applied for annealing other types of electrical components of various microscale integrated circuit devices.