Diamond NV-14N Atomic Clock Using Ramsey-Locked Nuclear Spin Reference
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Solution Overview
Problem
Current atomic clocks, particularly Rubidium-based ones, suffer from low accuracy and poor long-term stability due to environmental perturbations and complex lattice environments in solids, limiting their precision and robustness for applications requiring high-precision timekeeping.
Innovation Solution
Implementing an atomic clock based on the NV-14N coupling spin system in diamond using Ramsey interferometry to lock a radiofrequency frequency to the 14N zero-field splitting, utilizing a combination of laser, microwave, and radiofrequency pulses for initialization, Ramsey interferometry, readout, and frequency feedback to achieve a stable frequency standard.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the zero-field splitting of the NV center is used as a frequency standard, then the atomic clock can be miniaturized and operated at room temperature, but the frequency stability deteriorates due to temperature sensitivity (−74 kHz/K)
Solution Approach 1:
The patent uses the 14N nuclear spin as an intermediary to transfer the frequency reference function from the temperature-sensitive NV electron spin to the temperature-insensitive nuclear spin. The NV center serves as a mediator that can be initialized and read out, while the actual frequency standard is the 14N zero-field splitting which is insensitive to temperature changes.
Solution Approach 2:
The patent extracts the frequency reference function from the NV electron spin system and transfers it to the 14N nuclear spin system. By separating the initialization/readout function (NV electron spin) from the frequency reference function (14N nuclear spin), the system achieves both room temperature operation and temperature-insensitive frequency stability.
2Measurement precision
If atomic gases are used for frequency reference, then the transition frequency is well-defined, but the coherence time is short due to Doppler broadening and collision broadening
Solution Approach 1:
The patent changes the physical state parameter from gas phase to solid phase (diamond lattice). This parameter change eliminates Doppler broadening and collision broadening effects that limit coherence time in atomic gases, while the NV-14N coupling system in the solid diamond lattice maintains a well-defined transition frequency for the 14N nuclear spin.
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
The NV-14N coupling spin system in diamond provides a robust and stable frequency standard, achieving high precision and long-term stability, comparable to commercial atomic clocks, with improved resistance to external disturbances like temperature and magnetic fields.
Implementation Method 1
comparing a RF frequency with a 14N zero-field splitting through Ramsey interferometry
Implementation Method 2
applying a laser pulse to initialize NV electron spins
Implementation Method 3
applying a selective π microwave pulse
Implementation Method 4
applying a π radiofrequency pulse to initialize 14N nuclear spins
Implementation Method 5
reading out a difference value between the RF frequency and the 14N zero-field splitting by collecting a fluorescence signal from NV centers
Implementation Method 6
comparing a RF frequency with a 14N zero-field splitting through Ramsey interferometry
Data Source
AI summary
A method for implementing an atomic clock based on NV-14N coupling spin system in diamond and a device are provided. The method is to lock a RF frequency using a 14N zero-field splitting and output the RF frequency as a frequency standard. The method includes: applying a pulse sequence to jointly initialize NV electron spins and 14N nuclear spins; performing a Ramsey interferometry to compare a RF frequency and a 14N zero-field splitting; entangling the NV electron spin and the nuclear spin, reading out a state of nuclear spins by collecting a fluorescence signal; calculating a frequency difference between the RF frequency and the 14N zero-field splitting according to the fluorescence signal, thereby locking the RF frequency to the 14N zero-field splitting; and outputting the RF frequency as a frequency standard.