Interferometric Pendulum Gravimeter for Transverse Gravity Detection
Solution Overview
Problem
Current precision gravimetry methods for measuring gravitational fields transverse to the Earth's gravitational field are limited by the need for complex and expensive equipment, such as vacuum systems and cryostats, and lack portable and inexpensive solutions with sufficient sensitivity for geological and industrial applications.
Innovation Solution
A gravimeter system utilizing a magnetically damped pendulum and a displaced Sagnac interferometer to measure tilt changes induced by gravitational fields, achieving high sensitivity without the need for vacuum or cryogenic conditions, using a light source, beam splitter, beam combiner, and detector to analyze interference patterns and calculate gravitational field strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional precision gravimetry methods are used to measure gravitational fields transverse to Earth's field, then measurement precision can be achieved, but device complexity and cost increase due to requirements for vacuum systems and cryostats
Solution Approach 1:
The patent replaces complex mechanical and cryogenic systems with a magnetically damped pendulum and optical interferometer system. The pendulum uses magnetic damping instead of mechanical friction, and the interferometer uses laser light interference to detect tilt changes, eliminating the need for vacuum and cryogenic equipment while maintaining high measurement precision of 100 fm/s² to 500 pm/s²
Solution Approach 2:
The patent changes the operating parameters by using a magnetically damped pendulum with critical damping time of 10's of milliseconds to seconds, and operating the interferometer at ambient temperature and pressure. This allows the system to achieve high sensitivity without requiring the extreme conditions (vacuum, cryogenic temperatures) needed by traditional gravimeters
2Measurement precision
If traditional precision gravimetry equipment is deployed, then gravitational field measurement capability is achieved, but portability and ease of operation deteriorate due to heavy and complex equipment
Solution Approach 1:
The patent replaces heavy mechanical support structures and environmental control systems with a compact optical table and magnetic damping system. The interferometer uses laser beams and optical components that can be mounted on a stable table, eliminating the need for heavy vacuum chambers and cryogenic equipment, making the system portable and easier to operate in field conditions
Solution Approach 2:
The magnetically damped pendulum is self-regulating through critical damping, automatically returning to equilibrium position without requiring active control systems. The interferometer automatically detects tilt changes through light interference patterns, eliminating the need for complex control and calibration systems that would reduce portability
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 system provides sensitivity of 100 fm/s2 to 500 pm/s2 after one second of integration, enabling the detection of gravitational fields transverse to the Earth's field, including those from target objects, with potential applications in oil exploration, mining, and geological imaging without the need for expensive or complex equipment.
Implementation Method 1
A beam splitter may be disposed along the beam path and configured to split light from the light source along a first path and a second path
Implementation Method 2
Light directed along the first path may be configured to reflect off the pendulum at a first position. Light directed along the second path may be configured to reflect off the pendulum at a second position different than the first position
Implementation Method 3
A beam combiner may be provided that is configured to combine light direct along the first path and reflected off the pendulum at the first position with light directed along the second path and reflected off the pendulum at the second position
Implementation Method 4
A detector may be provided and configured to receive the light combined by the beam splitter
Implementation Method 5
the pendulum is magnetically damped, and critically damped in some instances
Data Source
AI summary
Embodiments of the present invention may be generally related to methods, devices, and systems which measure a gravitational field. The methods and devices may utilize an interferometer to measure tilt of a pendulum, where the tilt of the pendulum is due to a gravitational force associated with a target object. In some embodiments, the interferometer may be a displaced, even parity, Sagnac interferometer. Additionally, the interferometer may be operated in the inverse weak value domain. In some embodiments, the pendulum and interferometric readout may measure relative gravitational fields that are transverse to Earth's gravitational field. In at least some embodiments, methods and devices may have shot noise limited sensitivity sufficient to detect one kilogram 25 meters away and may have a 1 nGal resolution after mere seconds of integration. Embodiments disclosed may be used to gravitationally map density fluctuations in a target object, including the human body.