Image-Rotating Optical Parametric Oscillator for Thermal Load Sharing
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Solution Overview
Problem
Conventional laser systems produce a single color output in a fixed spectral line in the infrared spectrum, and scaling them to higher energy and repetition rates is limited by thermal effects in nonlinear optical crystals, which degrade beam quality and efficiency.
Innovation Solution
A novel optical parametric oscillator design using multiple nonlinear optical crystals with specific crystal cuts and an image rotating architecture to mitigate thermal gradients and phase shifts, allowing higher energy and repetition rates without compromising beam quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional laser systems are scaled to higher energy and repetition rates, then power output is improved, but thermal effects in nonlinear optical crystals degrade beam quality and efficiency
Solution Approach 1:
The system divides the single nonlinear optical crystal into multiple separate nonlinear optical crystals arranged in series. Each crystal handles a portion of the total power conversion, distributing the thermal load across multiple components rather than concentrating it in a single crystal. This segmentation allows higher overall power output while maintaining beam quality by preventing excessive thermal effects in any individual crystal.
Solution Approach 2:
The invention introduces a temporal dimension to the optical path by implementing an image rotating architecture where the beam traverses through multiple crystals at different angular orientations over time. The rotating image scanner alternates the beam path between multiple crystals, effectively distributing the thermal burden across both spatial (multiple crystals) and temporal (rotating sequence) dimensions, enabling high power operation without compromising beam quality.
2Productivity
If conventional laser systems operate at higher repetition frequencies, then productivity is improved, but thermal effects in nonlinear optical crystals degrade efficiency
Solution Approach 1:
By segmenting the nonlinear optical conversion process across multiple crystals, each crystal operates at a lower individual power density even at high repetition frequencies. This reduces the cumulative thermal effects that would otherwise cause efficiency degradation, allowing the system to maintain high conversion efficiency while operating at elevated repetition rates for improved productivity.
Solution Approach 2:
The image rotating architecture implements periodic switching between multiple crystal elements, where each crystal is activated in sequence rather than continuously. This periodic action allows thermal diffusion between pulses, preventing heat accumulation that would reduce conversion efficiency at high repetition frequencies, thereby maintaining energy efficiency while achieving high productivity.
3Reliability
If thermal effects are reduced to maintain beam quality, then reliability is improved, but power output is limited
Solution Approach 1:
The system merges multiple nonlinear optical crystals into a unified optical train where each crystal contributes to the overall power conversion. By combining the capabilities of multiple crystals in series with the image rotating architecture, the system achieves both high power output and maintained beam quality, as each crystal operates within safe thermal limits while collectively delivering high total power.
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 system generates tunable light in the visible spectrum at higher energies (>200 mJ) and repetition frequencies (100's of Hz) with maintained beam quality and efficiency.
Implementation Method 1
an image rotating optical parametric oscillator configured to receive both the pump beam of light and the signal or idler wave seed as inputs, and generate an idler beam of light having a first color and a signal beam of light having a different second color
Implementation Method 2
at least one non-linear optical crystal with a crystal axis cut such that the idler beam propagates in a first direction that is different than a second direction in which the signal beam propagates through the at least one non-linear optical crystal
Data Source
AI summary
An image rotating optical parametric oscillator, comprising: optical elements that are (i) located and oriented to form a non-planar, image-rotating ring cavity and (ii) configured to rotate a resonating beam by a defined number of degrees for each round trip in the cavity; and non-linear optical crystal(s) configured to convert energy of a pump beam of light into an idler beam of light having a first color and a signal beam of light having a different second color; wherein the non-linear optical crystal(s) is (are) cut such that the idler beam of light propagates in a first direction that is different than a second direction in which the signal beam of light propagates through the at least one non-linear optical crystal; and wherein a power of the signal beam of light exiting the image rotating optical parametric oscillator is three to six magnitudes larger than a power of the signal or idler wave seed.