Laser-Based Phase Modulation for Electron Microscopy
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Solution Overview
Problem
Conventional phase contrast electron microscopes face challenges in achieving high contrast and long-term stability due to the deterioration of phase plates under electron beam radiation, leading to reduced image quality and increased electron beam dosage on sensitive specimens like soft living organisms and non-staining resins.
Innovation Solution
A phase contrast transmission electron microscope apparatus utilizing laser beams to modulate electron phases without absorbing electrons, featuring a first and second laser beam irradiation process with electric fields parallel to electron beam propagation, and a third laser beam for focus modulation, enabling adjustable phase modulation and minimizing electron beam dosage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Zernike phase plate is used to convert electron beam phases into contrast, then phase contrast imaging is achieved, but the phase plate deteriorates under electron beam radiation leading to reduced image quality and shortened device lifetime
Solution Approach 1:
The patent replaces the mechanical phase plate system with a laser-based phase modulation system. Instead of using a physical carbon film phase plate that deteriorates under electron beam radiation, the invention uses laser beams to modulate the electron beam phases through electromagnetic interaction, eliminating the mechanical component that causes reliability issues while maintaining phase contrast imaging capability
Solution Approach 2:
The patent introduces laser beams as an intermediary to achieve phase modulation. The laser beams act as a mediator between the electron source and the specimen, modulating electron beam phases through electromagnetic interaction without requiring direct contact with a physical phase plate, thereby avoiding the deterioration problem while maintaining imaging quality
2Measurement precision
If conventional phase plates are positioned on the focal plane to modulate electron beam phases, then phase contrast is achieved, but electron beam absorption increases the dosage required on the specimen
Solution Approach 1:
The patent replaces the absorbing mechanical phase plate with a non-absorbing laser-based modulation system. The laser beams modulate electron phases through electromagnetic fields without absorbing electrons, thereby reducing the electron beam dosage required on the specimen while maintaining phase contrast capability
Solution Approach 2:
The laser beams serve as an intermediary that modulates electron phases without absorption. This intermediary approach allows phase contrast to be achieved through electromagnetic interaction rather than physical absorption, reducing the quantity of electron beams needed on the specimen
3Measurement precision
If soft living organisms or non-staining resins are observed using conventional electron microscopy, then structural imaging is attempted, but insufficient electron beam absorption results in poor contrast
Solution Approach 1:
The patent replaces the conventional absorption-based contrast mechanism with laser-mediated phase modulation. This allows phase contrast imaging of low-absorption specimens like soft living organisms without requiring high electron beam dosages that would cause damage, achieving both good contrast and reduced harmful effects
Solution Approach 2:
The patent changes the contrast mechanism from absorption-based to phase-based modulation. By using laser beams to modulate electron phases, the system can achieve high contrast for specimens with low electron beam absorption while using lower electron dosages, thereby reducing damage to sensitive biological specimens
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
This approach allows for high-contrast imaging with extended apparatus lifetime, minimizing electron beam waste and maintaining specimen integrity by achieving phase and amplitude measurements without damaging the phase modulating components.
Implementation Method 1
a first laser beam irradiating means for radiating laser beams having direction of an electric field parallel with propagating direction thereof, onto said electron beams, on a focal plane behind said object lens
Data Source
AI summary
A phase contrast transmission electron microscope apparatus has a long-life phase modulator, enabling changes in quantity of phase modulation, barely absorbing the electron beams, and not being influenced by irradiation of the electron beams. An electron microscope comprises an electron gun, a first laser beam irradiating process, being positioned between the electron source and an object lens, for irradiating laser beams onto the electron beams radiated from the electron gun, a second laser beam irradiating process, being positioned on a focal plane behind the object lens, for focusing and irradiating the laser beams upon the focus of the electron beams penetrating through a specimen, and a screen or a 2D electron sensor for detecting a specimen image in the form of distribution of intensity of the electron beams by an optical system.