Electron Beam Splitter Using Oscillating Electric Fields
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Solution Overview
Problem
Current electron beam splitters in electron microscopy suffer from significant beam loss, limited splitting capability, and sensitivity to external interference, making them unsuitable for high-resolution and low-radiation applications.
Innovation Solution
An electron beam splitter utilizing a multi-pole electrode arrangement subjected to high-frequency alternating voltage, generating oscillating electric fields that create a pseudopotential with a single local minimum on the input side and multiple local minima on the output side, allowing for efficient and large-scale beam splitting without forward energy loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an electrostatic biprism is used to split the electron beam, then the beam can be diffracted, but a portion of the electron beam inevitably hits the biprism filament and is lost
Solution Approach 1:
The patent replaces the mechanical electrostatic biprism system with a standing light wave optical system. Instead of using a physical charged filament that blocks and diffracts electrons, the invention uses a Kármán-Dirac optical grating where a standing light wave modulates the electron beam through optical forces, eliminating direct contact and beam loss on a physical structure.
Solution Approach 2:
The patent introduces light (electromagnetic field) as an intermediary between the electron beam and the splitting mechanism. The standing light wave acts as a mediator that transfers momentum to electrons through optical forces, enabling beam splitting without requiring direct interaction with a physical biprism structure.
2Loss of energy
If diffraction at a crystal is used for beam splitting, then beam splitting is achieved, but losses occur in higher diffraction orders
Solution Approach 1:
The patent changes the fundamental parameter of the splitting mechanism from crystal lattice diffraction to optical field modulation. By using a standing light wave with adjustable frequency and intensity, the system can control electron distribution in first and higher diffraction orders without the inherent losses of crystal diffraction, as the optical potential can be dynamically tuned.
3Loss of energy
If a double slit is used to split the electron beam, then beam splitting is achieved, but transmission is low
Solution Approach 1:
The patent replaces the mechanical double-slit structure with an optical standing wave field. Instead of electrons passing through physical slits that block most of the beam, the standing light wave creates a periodic potential that guides electrons into multiple trajectories, dramatically improving transmission efficiency while maintaining splitting capability.
4Loss of energy
If a magnetic biprism is used for beam splitting, then beam splitting is achieved, but the transmission of electrons through magnetic material is reduced, resulting in a reduction in coherence
Solution Approach 1:
The patent replaces the magnetic field-based splitting mechanism with an optical field-based mechanism. Instead of electrons passing through magnetic material that reduces transmission and coherence, the standing light wave creates an optical potential that interacts with electrons without requiring them to traverse magnetic matter, preserving both transmission and coherence.
5Length of stationary object
If an electron beam splitter is designed to achieve large beam splitting for sample placement, then a large separation is achieved, but the system becomes more sensitive to external interference and less robust
Solution Approach 1:
The patent uses a standing light wave with high frequency oscillation to create the beam splitting effect. The periodic nature of the optical field provides a stable, controllable potential landscape that can maintain large beam separation while being less susceptible to external disturbances, as the rapid oscillation averages out many perturbations.
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 solution enables loss-free and adiabatic splitting of electron beams with minimal momentum change, suitable for interferometric applications, and is robust against external disturbances, facilitating high-resolution imaging with reduced radiation exposure.
Implementation Method 1
the electrode arrangement having a first number of electrodes to which voltage is applied on the entry side generates a first oscillating electric field
Implementation Method 2
which forms a single local inclusion minimum in a transverse plane averaged over time
Implementation Method 3
a stable transverse confinement of charged particles can be generated, which can be described by a time-averaged pseudopotential
Implementation Method 4
the linear Paul trap is based on alternating quadrupole electric fields
Implementation Method 5
higher-order multipole fields can also generate pseudopotentials according to this principle, which have two or more locally separate inclusion minima
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The invention relates to an electron beam splitter (1) comprising a multi-pole electrode arrangement (5) which can be supplied with a high-frequency AC voltage and which extends along a specified path (6) from an inlet side (9) to an outlet side (10). The electrode arrangement (5) generates a first oscillating electric field (61) at the inlet side (9) by means of a first number of electrodes (7) supplied with a voltage, said electric field forming a single local confinement minimum (62) on a transversal plane in a time-averaged manner, and the electrode arrangement (5) generates a second oscillating electric field (65) at least at the outlet side (10) by means of a second number of electrodes (7) supplied with a voltage, said electric field forming at least two local confinement minima (66, 67) on a transversal plane in a time-averaged manner.