Solid Immersion Lens TIRFM Breaks Diffraction Limits
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Solution Overview
Problem
Conventional optical microscopes, including TIRFM, face limitations in horizontal resolution due to diffraction limits and the restricted numerical aperture of oil immersion lenses, which restricts the imaging capability, especially in observing thin specimens like cell surfaces.
Innovation Solution
A TIRFM system incorporating a solid immersion lens (SIL) and stimulated emission depletion (STED) technology, where an aperture adjusts the excitation light to exceed the threshold angle for total internal reflection, combining excitation and de-excitation light to enhance resolution beyond diffraction limits, using a high refractive index SIL to increase numerical aperture and collect fluorescent light efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional oil immersion lens is used, then the microscope can achieve total internal reflection fluorescence imaging, but the horizontal resolution is limited by diffraction and the numerical aperture is limited to 1.49
Solution Approach 1:
The patent changes the refractive index parameter by replacing the oil immersion lens with a solid immersion lens made of high-refractive-index material (n≥1.8). This parameter change enables the numerical aperture to exceed 1.49, thereby achieving horizontal resolution beyond the diffraction limit while maintaining the total internal reflection fluorescence imaging capability
Solution Approach 2:
The patent employs a solid immersion lens that replicates and enhances the functionality of the conventional oil immersion lens while achieving superior performance. The solid immersion lens copies the light-focusing function but with enhanced refractive properties that break the diffraction limit, providing both horizontal and vertical resolution improvement
2Measurement precision
If a solid immersion lens with high refractive index is used, then the numerical aperture increases and horizontal resolution improves, but the device structure becomes more complex
Solution Approach 1:
The patent achieves enhanced horizontal resolution by changing the refractive index parameter of the immersion medium from oil (n≈1.5) to solid material (n≥1.8). This single parameter change enables the numerical aperture to exceed conventional limits, providing diffraction-free resolution without requiring multiple lens components
Solution Approach 2:
The patent extracts and eliminates the oil immersion component from the system, replacing it directly with a solid immersion lens. This extraction simplifies the overall device structure by removing the need for oil handling mechanisms while achieving superior optical performance through the solid material's higher refractive index
3Measurement precision
If the excitation light angle is adjusted to exceed the threshold angle for total internal reflection, then vertical resolution improves, but the light collection efficiency may be reduced
Solution Approach 1:
The patent changes the refractive index parameter of the solid immersion lens to enable total internal reflection at the interface between the solid lens and the specimen. This parameter change allows excitation light to be directed at angles exceeding the critical angle, creating evanescent waves that provide enhanced vertical resolution while the high refractive index material compensates for light collection efficiency
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 configuration achieves resolutions beyond conventional optical diffraction limits in both horizontal and vertical directions, enabling high-contrast imaging of thin specimen surfaces with improved image contrast and resolution.
Implementation Method 1
a solid immersion lens to which the light discharged from the optical body is incident, and configured to refract the light discharged from the optical body toward the specimen
Implementation Method 2
A total internal reflection of the light incident to the solid immersion lens occurs on a bottom of the solid immersion lens
Implementation Method 3
an excitation light source configured to emit an excitation light that excites the fluorescent substance to emit fluorescence
Implementation Method 4
a de-excitation light source configured to emit a de-excitation light that de-excites the fluorescent substance excited by the excitation light emitted from the excitation light source
Data Source
AI summary
Disclosed is a fluorescence microscope for imaging a specimen containing a fluorescent substance, the fluorescence microscope including an excitation light source configured to emit an excitation light that excites a fluorescent substance to emit fluorescence; a de-excitation light source configured to emit a de-excitation light that de-excites the fluorescent substance excited by the excitation light emitted from the excitation light source; an optical body configured to overlap a light emitted from the excitation light source and a light emitted from the de-excitation light source, and to discharge the overlapped light toward the specimen; and a solid immersion lens to which the light discharged from the optical body is incident, and configured to refract the light discharged from the optical body toward the specimen. A total internal reflection of the light incident to the solid immersion lens occurs on a bottom of the solid immersion lens.