Multi-Ring Mask Layout for Sub-Diffraction Light Focusing
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Solution Overview
Problem
Conventional light irradiation apparatuses struggle with focusing light on regions smaller than the diffraction limit, often resulting in unintended focusing and reduced spatial resolution due to aberrations and side lobes.
Innovation Solution
A multi-ring mask with specific radial width relationships between light-shielding and transmitting areas, used in conjunction with a focusing optical system, to spatially modulate input light and enhance focusing precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a single-ring mask or conventional multi-ring mask is used to focus light below the diffraction limit, then sub-diffraction focusing is achieved, but light may be focused on unintended regions and the focusing region size/shape may deviate from intended specifications
Solution Approach 1:
The patent applies local quality by making the radial width of light-shielding areas locally larger than transmitting areas at specific angular positions. This non-uniform local modification of the mask structure suppresses side lobes in specific directions while maintaining sub-diffraction focusing capability, thereby improving both focusing precision and reliability
Solution Approach 2:
The patent changes the geometric parameters of the multi-ring mask by setting the radial width of light-shielding areas to be larger than that of transmitting areas. This parameter modification optimizes the interference pattern of light waves, enabling simultaneous achievement of sub-diffraction focusing and suppression of unintended focusing regions
2Measurement precision
If conventional multi-ring masks are used, then light can be focused on regions smaller than the diffraction limit, but side lobes caused by aberrations reduce spatial resolution
Solution Approach 1:
The patent converts the harmful side lobes caused by aberrations into beneficial suppression by strategically designing larger radial widths for light-shielding areas. This design exploits the interference of light waves to cancel out side lobe formations, thereby improving spatial resolution while maintaining sub-diffraction focusing
Solution Approach 2:
By making the radial width of light-shielding areas locally larger than transmitting areas at specific angular positions, the patent creates non-uniform light distribution that suppresses side lobes in specific directions, thereby improving spatial resolution without sacrificing sub-diffraction focusing capability
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 multi-ring mask enables efficient focusing of light on regions smaller than the diffraction limit, improving spatial resolution and reducing aberration-induced side lobes, thereby enhancing the performance of optical and photoacoustic microscopes.
Implementation Method 1
a multi-ring mask for spatially intensity-modulating input light in a beam cross-section and outputting modulated light, and includes a plurality of ring-shaped light-shielding areas provided around a center position; a transmitting area provided between two adjacent light-shielding areas
Implementation Method 2
a focusing optical system for focusing light output from the light source
Implementation Method 3
it is known that a beam waist diameter, being a measure of a size of a focusing diameter, can be reduced to only about half a wavelength of the light. This is called a diffraction limit
Implementation Method 4
At the focusing position, two light beams interfere with each other, so that light can be focused on a region smaller than the diffraction limit
Data Source
AI summary
A light irradiation apparatus focuses light on a surface or an inside of an object to observe or process the object, and includes a laser light source, a lens, a lens, a mask, a wave plate, and a lens. The mask is a multi-ring mask for spatially intensity-modulating input light in a beam cross-section and outputting modulated light, and includes a plurality of ring-shaped light-shielding areas provided around a center position, and a transmitting area provided between two adjacent light-shielding areas out of the plurality of light-shielding areas. A radial width of each of the two adjacent light-shielding areas out of the plurality of light-shielding areas is larger than a radial width of the transmitting area provided between the two light-shielding areas.