Levitated Particle Electric Field Measurement
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Solution Overview
Problem
Current electric field measurement methods lack sensitivity and spatial resolution, particularly for weak electric fields, and are limited in detecting vector electric fields effectively.
Innovation Solution
A method and apparatus using a levitated particle to measure electric fields by adjusting its electric charge and detecting displacement power spectral density, allowing for high-sensitivity and high-resolution vector electric field measurement through optical or magnetic levitation and high-voltage corona discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If antenna coupling circuit is used for electric field measurement, then the device structure is simple, but the detection sensitivity is low (1 to 10 V/m/Hz1/2)
Solution Approach 1:
The patent replaces traditional electronic measurement systems (antenna coupling circuits) with a mechanical measurement system using a levitated particle as a test mass. The particle's mechanical displacement in response to electric field forces is measured with high precision, achieving sensitivity of 10^-3 V/m/Hz1/2 or higher while maintaining relative structural simplicity
Solution Approach 2:
The patent changes the measurement parameter from direct electrical signal detection to mechanical displacement detection of a levitated particle. By measuring the particle's position fluctuations and relating them to applied electric field forces through calibrated relationships, the system achieves enhanced sensitivity
2Adaptability or versatility
If electro-optic crystal measurement method is used, then the detection sensitivity reaches 10−3 V/m/Hz1/2, but only one direction of the electric field can be detected
Solution Approach 1:
The patent segments the electric field measurement into three independent orthogonal components by measuring the particle's displacement along each axis separately. The particle responds to electric field forces in x, y, and z directions independently, allowing full vector field reconstruction while maintaining high sensitivity for each component
Solution Approach 2:
The patent transitions from one-dimensional measurement (single direction) to three-dimensional measurement by utilizing the particle's ability to respond to forces in all spatial dimensions. The levitated particle's position can be tracked in 3D space, enabling complete vector electric field characterization
3Adaptability or versatility
If NV color center or Rydberg atoms method is used, then the detection sensitivity is related to atomic energy level, but the optimal detection frequency band is limited to microwave and GHz-THz frequency band
Solution Approach 1:
The patent changes the detection mechanism from atomic energy level transitions to mechanical oscillation of a levitated particle. The particle's resonant frequency can be tuned by adjusting trap stiffness and particle properties, enabling sensitive detection across a broad frequency range from DC to MHz and beyond, unrestricted by atomic transition frequencies
4Measurement precision
If a larger particle is used for levitation, then the particle is easier to capture and levitate, but the spatial resolution of electric field measurement decreases
Solution Approach 1:
The patent replaces conventional mechanical trapping methods with optical trapping using highly focused laser beams. This allows stable levitation of sub-micron particles ( achieving nanometer-scale spatial resolution) by balancing optical gradient forces against gravity and drag forces
Solution Approach 2:
The patent utilizes controlled mechanical vibration and resonance of the levitated particle to enhance detection sensitivity. By driving the particle at its resonant frequency and measuring the amplified response to electric field forces, the system achieves high sensitivity with minimal particle mass
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 method achieves high sensitivity and spatial resolution for electric field detection, capable of measuring electric fields in the DC-MHz range with nanometer-scale resolution and wide spectral detection, enabling precise vector electric field measurement.
Implementation Method 1
adjusting a quantity of electric charge carried by the levitated particle; the quantity of electric charge carried by the levitated particle is adjusted by ultraviolet excitation or high-voltage corona discharge
Implementation Method 2
the captured particle is levitated by optical levitation, magnetic levitation or electrical levitation
Implementation Method 3
measuring a displacement power spectral density (PSD) Svxel of the levitated particle under the electric field to be measured
Data Source
AI summary
A method for electric field measurement based on a levitated particle includes steps of (1) capturing a particle and levitating the captured particle; (2) adjusting a quantity of electric charge carried by the levitated particle; (3) measuring a charge number N of the levitated particle; (4) disposing the levitated particle in an electric field to be measured, measuring a displacement power spectral density Svxel of the levitated particle under the electric field and obtaining an electric field force Fel; and (5) according to a formula of E=Fel/Nqe, obtaining an electric field intensity E. An apparatus for electric field measurement based on a levitated particle includes a high-voltage DC (direct current) power supply, two bare wire electrodes, a vacuum chamber, a trapping laser, an objective lens, a pair of parallel electrodes, a collective lens, a quadrant photodetector, a lock-in amplifier, a signal generator and a power amplifier.