Fluorescent Lens Photodetection for Wide-Angle Laser Reception
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Solution Overview
Problem
Existing optical detection systems face challenges in free-space communications due to narrow laser beams, small detector areas, and limited field-of-view, requiring complex mechanical alignment or bulky optics, which are inefficient for detecting narrow beams over wide angles.
Innovation Solution
A fluorescent lens with a larger light collection area and dispersed fluorophore that emits light at any angle, coupled with a photodetector, allowing omnidirectional detection through a smaller outcoupling area, and optionally using dichroic mirrors for enhanced signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a larger photodetector area is provided to collect more signals, then the signal collection capability is improved, but the detector response becomes slow which is unsuitable for free-space communications
Solution Approach 1:
The patent transitions from a planar photodetector surface to a three-dimensional spherical fluorescent lens. The light collecting area is the entire spherical surface area, while the light outcoupling area is a small portion of the sphere. This dimensional transformation allows the photodetector to maintain a small active area for fast response while achieving a large effective light collection area through the spherical geometry and omnidirectional light gathering capability.
2Volume of stationary object
If a bulky optical lens is used to collect signals over larger distance, then the signal collection range is improved, but the device becomes large and the field-of-view is limited to less than 70° half angle
Solution Approach 1:
The patent employs a spherical fluorescent lens instead of traditional bulky optical lenses. The spherical geometry provides omnidirectional light collection capability with a field-of-view exceeding 180°, eliminating the limited field-of-view constraint of conventional lenses. The curved spherical surface naturally gathers light from all directions without requiring large physical dimensions.
3Adaptability or versatility
If a fish-eye lens is used to increase field-of-view and collection efficiency, then the detection angle is improved up to 180°, but it is not effective for lasers with narrow beams
Solution Approach 1:
The patent changes the detection mechanism from direct optical focusing to fluorescent conversion. The fluorescent lens absorbs narrow laser beams at any incident angle and converts them to omnidirectionally emitted light that can be efficiently collected by the photodetector. This parameter change in the detection principle allows effective detection of both narrow laser beams and wide-angle signals, overcoming the limitation of fish-eye lenses.
4Measurement precision
If mechanical laser tracking system is used to align the beam, then the alignment precision is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical laser tracking and alignment systems with a passive optical solution. The spherical fluorescent lens inherently collects light from all directions without requiring mechanical adjustment or active tracking. This substitution eliminates moving parts, reduces device complexity, and maintains high detection precision through the omnidirectional light gathering capability of the spherical geometry.
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 omnidirectional photodetection with high sensitivity and fast response, capturing light from 0° to 360° without critical alignment, and supports high-frequency modulation, improving signal detection and intensity.
Implementation Method 1
a fluorophore dispersed throughout the light collecting area and the fluorescent lens, wherein the fluorophore is excitable by a light beam, which is incident at any position or angle in relation to the light collecting area, to produce a light emission
Implementation Method 2
a fluorophore dispersed throughout the light collecting area and the fluorescent lens, wherein the fluorophore is excitable by a light beam, which is incident at any position or angle in relation to the light collecting area, to produce a light emission
Implementation Method 3
the fluorescent lens is configured to focus the light beam, which is incident on the spherical surface and unconverted by the fluorophore, on the light outcoupling area
Data Source
AI summary
Disclosed are optical detection device, system, and method which increase photodetection area and enables omnidirectional and self-aligning photodetection through the use of a fluorescent lens. An optical detection device comprises a fluorescent lens having a light collecting area being a spherical, hemispherical, or cylindrical surface of the fluorescent lens, and a light outcoupling area; and a fluorophore dispersed throughout the light collection area and the fluorescent lens, wherein the fluorophore is excitable by a light beam, which is incident at any position or angle in relation to the spherical surface, to produce a light emission, wherein the light outcoupling area is arranged to allow an extraction of the light emission from the fluorescent lens, wherein the light collecting area is larger than the light outcoupling area.