Optical Carrier for Evanescent Wave Detection in Small Volumes
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Solution Overview
Problem
Current methods for optical detection in small sample volumes are limited by the short range of evanescent waves, which restricts the probing depth and can lead to the detection of non-specifically bound particles, and require complex setups for fluid control and illumination.
Innovation Solution
A carrier with an optical structure that refracts and collects light from a sample chamber, allowing for simultaneous illumination and detection from the same side, enabling deeper probing with adjustable volume and specific detection of surface-bound particles using a combination of facets for excitation and collection of light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If evanescent waves are used for optical detection, then the detection can be restricted to small volumes, but the probing depth is limited and non-specifically bound particles cannot be distinguished
Solution Approach 1:
The optical structure is segmented into multiple facets with different orientations. Some facets are oriented to excite evanescent waves for shallow detection, while other facets are oriented at different angles to allow light penetration at greater depths. This segmentation enables simultaneous detection at multiple depths, allowing distinction between specifically bound particles (at the interface) and non-specifically bound particles (at greater depths).
Solution Approach 2:
Different regions of the optical structure have different local optical properties. Facets with different orientations create local variations in evanescent wave penetration depth. By assigning different detection functions to different local regions, the system achieves both shallow interface detection and deeper volume detection within the same structure.
2Measurement precision
If complex setups are used for fluid control and illumination, then detection sensitivity can be improved, but device complexity increases
Solution Approach 1:
The optical structure serves multiple functions simultaneously: it acts as both the illumination source (by directing light at the interface) and the detection device (by collecting scattered light). The same facets that generate evanescent waves also collect the scattered light from particles. This multi-functionality eliminates the need for separate illumination and detection systems, reducing device complexity while maintaining detection sensitivity.
Solution Approach 2:
The illumination path and detection path are merged into a single optical structure. Light is directed at the optical interface, evanescent waves are generated, scattered light from particles is collected by the same structure, and the signal is detected. This merging of functions simplifies the overall system architecture while preserving the sensitivity benefits of evanescent wave detection.
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 precise detection of target components in small volumes, enhancing sensitivity and specificity by enabling the detection of particles bound to the surface while minimizing interference from unbound particles and fluid flow control complexities.
Implementation Method 1
an optical structure that can refract an input light beam, which impinges on said structure from the interior of the carrier, into the adjacent exterior space
Implementation Method 2
the optical structure shall be able to collect an output light beam impinging on it from the exterior space, i.e. from the sample chamber
Implementation Method 3
a light beam is directed through a transparent material to an optical interface, defined by the transition from the transparent medium to another, optically less dense material, where it is totally internally reflected
Implementation Method 4
Light of this beam that penetrates the optically less dense medium as an evanescent wave is scattered by microorganisms, molecules and/or other components at the optical interface
Implementation Method 5
Photons of the input light beam may directly pass over to the output light beam; they may however also be converted in some way, e.g. by absorption and re-emission, stimulated emission, or scattering
Data Source
AI summary
A carrier and an apparatus for optical detection of a sample in a sample chamber includes en optical structure for refracting an input light beam into the adjacent sample chamber and for collecting an output light beam from light that originates in the sample chamber from the input light beam. The optical structure includes grooves in the surface of the carrier in which the Input light beam is transmitted Over a short distance through a sample. The optical structure can also be used for a wetting detection.