Cathodoluminescence Optical Hub Alignment
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Solution Overview
Problem
Aligning a cathodoluminescence (CL) mirror over a sample to collect and direct photons emitted during electron beam interaction is time-consuming and challenging, especially when multiple analysis instruments are involved, leading to signal loss and inefficiency in preserving CL intensity, spectral, polarization, and angular resolved light emission information.
Innovation Solution
An optical hub system within the electron microscope's low-pressure environment, utilizing a port adjuster and linear actuators to position and redirect the CL light efficiently to various analysis instruments, allowing for fine alignment and reconfiguration without altering the optical hub components, and incorporating a movable filter mechanism and adjustable optical aperture for optimal signal routing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a CL mirror is aligned for each instrument, then each instrument can be optimized for specific signal analysis, but the alignment process becomes time-consuming and complex
Solution Approach 1:
The system segments the optical path by providing separate optimized optical paths for different analysis instruments (spectrometer, light sensor, etc.), while using a single movable mirror to selectively direct light to each instrument. This allows each instrument to have its own optimized path without requiring separate fixed mirrors for each.
Solution Approach 2:
The patent employs a movable mirror that can be dynamically repositioned to different angular positions to direct CL light to different instruments. This dynamic positioning replaces the need for multiple fixed mirrors, reducing alignment complexity while maintaining instrument-specific optimization.
2Loss of time
If multiple instruments are combined to share a CL mirror, then alignment time is reduced, but signal loss increases due to difficulty in directing light to different instruments
Solution Approach 1:
The movable mirror can be precisely positioned at different angular orientations to efficiently direct CL light to different instruments. This dynamic control minimizes signal loss by ensuring optimal light coupling to each instrument's input, unlike fixed shared mirror arrangements that require compromise alignments.
Solution Approach 2:
The movable mirror acts as an intermediary device that selectively couples the CL light source to different instruments. By providing a controlled interface between the light source and multiple instruments, it enables efficient signal routing to each instrument without significant loss.
3Loss of energy
If fixed mirrors are used for each instrument, then signal preservation is optimized, but device complexity and space requirements increase
Solution Approach 1:
The patent merges the functions of multiple fixed mirrors into a single movable mirror system. By combining these elements, the system maintains the signal preservation benefits of dedicated optical paths while reducing the overall number of components and simplifying the mirror system architecture.
Solution Approach 2:
The movable mirror serves multiple functions by being able to direct light to different instruments at different times. This multi-functional element replaces what would otherwise require multiple dedicated mirrors, reducing device complexity while maintaining optimized signal paths.
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
Enables precise alignment and efficient transfer of CL light to multiple instruments with minimal signal loss, allowing for flexible instrument configuration and reduced need for fold mirrors and optical switches, thereby enhancing the analysis capabilities of CL signals.
Implementation Method 1
A common way to collect photons emitted via CL is via a collection-mirror, which may be a paraboloid mirror... the mirror focuses laser illumination from a transverse optical path onto the sample, and collects Raman and/or other scattered light, passing it back to an optical system
Implementation Method 2
When a high-energy charged particle, such as an electron or ion beam strikes a sample, photons can be emitted depending on the sample material. This phenomena is known as cathodoluminescence (CL)
Data Source
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AI summary
An apparatus for collection, distribution, and analysis of cathodoluminescence (CL) and other light signals in an electron microscope is provided. The optical hub, utilizing a linear-translating fold-mirror and mounted to the electron microscope, is used to receive essentially collimated light collected from a collection-mirror and efficiently route the collected light to a plurality of light-analysis instruments. The linear-translating fold-mirror can provide fine positional alignment of the light signal, and in an aspect of the invention can be used to select or scan a portion of the collected light-pattern into an optical slit or aperture. In one aspect, the optical hub includes a light filter mechanism that can track the movement of the fold-mirror. In an aspect, the optical hub also controls the positioning of the collection-mirror in proximity to the specimen being analyzed.