Retroreflector Spatially Distributed Laser Resonator
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Solution Overview
Problem
Distributed laser resonators using retroreflectors face challenges with optical image inversion issues, leading to non-overlapping beams, increased system complexity, and difficulties in placing optical components, which hinder practical application in wireless power transmission systems.
Innovation Solution
The use of retro-reflectors capable of reflecting beams co-linearly, combined with pupil imaging systems and additional optical components like telescopes and lenses, allows for co-linear operation, enabling efficient beam alignment and component placement within the laser cavity, overcoming the limitations of prior art systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If simple retroreflectors with opaque inversion points are used, then the system structure is simplified, but the beams do not overlap and optical components cannot be placed in the beam path
Solution Approach 1:
The invention extracts the inversion point from the optical path by using a retroreflector configuration where the inversion point is located outside the beam path. This allows the beams to overlap properly and enables placement of optical components in the beam path without being blocked by an opaque inversion point.
Solution Approach 2:
The patent introduces an intermediary optical element (such as a lens or mirror) that mediates between the retroreflector and the beam path, allowing the inverted beams to be realigned and overlapped while still permitting optical components to be placed in the path.
2Ease of operation
If telescope lens arrangements are used to handle two parallel beams, then beam handling capability is improved, but the system complexity increases and field of view is limited
Solution Approach 1:
Instead of using complex telescope arrangements to handle two separate beams, the invention inverts the approach by using a retroreflector that naturally produces overlapping beams, eliminating the need for additional beam-handling optics and reducing system complexity.
3Adaptability or versatility
If optical components with non-flat surfaces are placed in the beam path, then optical functions such as focusing are achieved, but the two beams become unparallel and the distributed resonator ceases lasing
Solution Approach 1:
The patent applies preliminary action by pre-aligning the retroreflector and optical components such that the beam inversion and optical manipulation occur in a predetermined sequence that maintains beam parallelism. The optical components are positioned and oriented in advance to ensure that despite beam inversion, the emerging beams remain parallel and lasing continues.
4Volume of moving object
If the inversion point is in an optically opaque location, then the retroreflector structure is compact, but optical access cannot be provided and beam overlap is prevented
Solution Approach 1:
The invention resolves the contradiction by moving the inversion point to a different spatial dimension or location that is not in the direct beam path. This allows the retroreflector to maintain a compact form factor while providing optical access and enabling beam overlap, as the inversion occurs in a location that does not obstruct the optical path.
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 enables efficient operation of distributed laser systems with co-linear beams, allowing for the placement of optical components that enhance field of view, beam focusing, and monitoring, while reducing system size and cost, and ensuring consistent lasing quality and safety standards.
Implementation Method 1
a first retroreflector comprising at least one optical component having at least one non-flat optical surface, and a second retro-reflector, both of said retro-reflectors being such that a beam incident on either is reflected back along a path coincident with that of the incident beam
Implementation Method 2
said gain medium is located at a pupil of said first retroreflector, said pupil being located at a position such that light passing at a plurality of angles through said at least one optical component or reflected at a plurality of angles from said at least one optical component, will be directed to said pupil
Implementation Method 3
a gain medium disposed between said first and second retro-reflectors
Data Source
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Figure 4A~5
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AI summary
A distributed resonator laser system using retro-reflecting elements, in which spatially separated retroreflecting elements define respectively a power transmitting and a power receiving unit. The retroreflectors have no point of inversion, so that an incident beam is reflected back along a path essentially coincident with that of the incident beam. This enables the distributed laser to operate with the beams in a co-linear mode, instead of the ring mode described in the prior art. This feature allows the simple inclusion of elements having optical power within the distributed cavity, enabling such functions as focusing/defocusing, increasing the field of view of the system, and changing the Rayleigh length of the beam. The optical system can advantageously be constructed as a pupil imaging system, with the advantage that optical components, such as the gain medium or a photovoltaic converter, can be positioned at such a pupil without physical limitations.