ODMR Magnetic Field Measurement Phase Synchronization
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Solution Overview
Problem
In Spin Echo Pulse Sequence, long time intervals between pulses make it difficult to measure low-frequency AC magnetic fields due to electron spin dispersion in ODMR materials, preventing proper measurement of low-frequency AC magnetic fields.
Innovation Solution
Synchronizing the DC magnetic field measurement Ramsey pulse sequence with the phase of the external AC signal, using a magnetic field measurement apparatus that includes an ODMR member, a coil for applying microwave fields, and a processor to control the measurement sequence and calculate magnetic flux density based on detected light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Spin Echo Pulse Sequence is used to measure AC magnetic field, then magnetic field measurement can be performed, but low-frequency AC magnetic fields cannot be properly measured when time intervals between pulses are long due to electron spin dispersion
Solution Approach 1:
The patent dynamically adjusts the time intervals between microwave pulses based on the frequency characteristics of the target AC magnetic field. By making the measurement sequence adaptive rather than fixed, the system can properly measure both low-frequency and high-frequency AC magnetic fields without suffering from electron spin dispersion issues that plague fixed-interval sequences.
Solution Approach 2:
The patent changes the temporal parameters (time intervals between pulses) of the measurement sequence to match the characteristics of the target magnetic field. Specifically, the intervals are adjusted according to the AC signal frequency, allowing the system to maintain measurement reliability across different frequency ranges by optimizing the pulse timing parameters.
2Adaptability or versatility
If time interval between pulses is increased to accommodate low-frequency AC signal, then low-frequency measurement becomes possible, but electron spin dispersion occurs in ODMR material
Solution Approach 1:
The patent employs periodic microwave pulse sequences where the timing is synchronized with the AC magnetic field period. This periodic action creates a resonant condition that maintains electron spin coherence even over longer measurement durations, preventing spin dispersion while enabling low-frequency measurement capability.
Solution Approach 2:
The patent applies preliminary microwave pulses to initialize and uniformize the electron spin state before the actual measurement begins. This preliminary action ensures that the spins are properly aligned and coherent at the start of the measurement sequence, extending the useful measurement window before dispersion occurs.
3Measurement precision
If DC magnetic field measurement Ramsey pulse sequence is synchronized with AC signal phase, then accurate low-frequency AC magnetic field measurement is achieved
Solution Approach 1:
The patent uses feedback from the detected optical signal to adjust and optimize the microwave pulse timing. By monitoring the ODMR signal in real-time and adjusting the pulse sequence parameters accordingly, the system achieves high measurement accuracy while the control complexity is managed through automated feedback loops rather than manual adjustment.
Data Source
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AI summary
An ODMR member (1) is arranged in a measurement target AC magnetic field. A coil (2) applies a magnetic field of a microwave to the ODMR member (1). A high frequency power supply (3) causes the coil (2) to conduct a current of the microwave. An irradiating device (4) irradiates the ODMR member (1) with light. A light receiving device (5) detects light that the ODMR member (1) emits. A measurement control unit (21) performs a predetermined DC magnetic field measurement sequence at a predetermined phase of the measurement target AC magnetic field, and in the DC magnetic field measurement sequence, controls the high frequency power supply (3) and the irradiating device (4) and thereby determines a detection light intensity of the light detected by the light receiving device (5). A magnetic field calculation unit (22) calculates an intensity of the measurement target AC magnetic field on the basis of the predetermined phase and the detection light intensity.