Kerr Mode-Locked Thin Disk Laser With Independent Mode Shaping
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Solution Overview
Problem
Conventional thin disk femtosecond lasers face limitations in achieving high pulse energies and short pulse durations due to thermal lensing, Q-switching instabilities, and complex cavity design requirements, particularly with SESAMs and Kerr lens mode-locking, which restrict power scalability and stability.
Innovation Solution
A laser device with a resonator design featuring independent mode shaping sections for the gain disc medium and Kerr medium, utilizing a concave-convex or telescopic cavity geometry to decouple beam adjustments, allowing for independent optimization of thermal lens sensitivity and mode sizes, thereby enhancing power scalability and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If Kerr lens mode-locking is used in conventional thin disk lasers, then pulse duration can be reduced, but thermal lensing and Q-switching instabilities occur which limit power scalability and stability
Solution Approach 1:
The resonator is divided into two independent mode shaping sections: a first section spanning the gain disc medium and a second section spanning the Kerr medium. This segmentation allows independent optimization of each section's beam parameters, enabling the Kerr lens mode-locking to achieve short pulses while the separate gain section maintains stable thermal management and avoids Q-switching instabilities.
Solution Approach 2:
Each mode shaping section is optimized for its specific function: the first section is designed to manage thermal lensing in the gain medium with appropriate beam waist and divergence, while the second section is optimized for Kerr lens mode-locking with different beam parameters. This local optimization allows each component to operate in its optimal regime without interfering with the other.
2Reliability
If SESAM mode locking is used, then stability is maintained, but pulse duration and power scalability are limited
Solution Approach 1:
The resonator is divided into two independent mode shaping sections: a first section spanning the gain disc medium and a second section spanning the Kerr medium. This segmentation allows independent optimization of each section's beam parameters, enabling the Kerr lens mode-locking to achieve short pulses while the separate gain section maintains stable thermal management and avoids Q-switching instabilities.
3Temperature
If the beam size in the gain disc medium is increased for better thermal management, then thermal lens sensitivity is reduced, but the mode size in the Kerr medium is affected which impacts mode-locking performance
Solution Approach 1:
The resonator is divided into two independent mode shaping sections: a first section spanning the gain disc medium and a second section spanning the Kerr medium. This segmentation allows independent optimization of each section's beam parameters, enabling the Kerr lens mode-locking to achieve short pulses while the separate gain section maintains stable thermal management and avoids Q-switching instabilities.
Solution Approach 2:
The resonator design provides universal beam shaping capability through two independent mode shaping sections that can be optimized for different functions simultaneously. The first section handles thermal management in the gain medium while the second section enables Kerr lens mode-locking, making the system adaptable to different operating conditions and gain media.
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 design achieves shorter pulse durations, such as 190 fs with 15 W average power, and increased stability, overcoming the limitations of conventional techniques by providing intrinsic scalability and improved thermal management, while maintaining stability comparable to SESAM mode locking.
Implementation Method 1
mode-locking Kerr medium
Data Source
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AI summary
A laser device (100), configured for generating laser pulses, has a laser resonator (10) with a gain disk medium (11) and a Kerr medium (12). The laser resonator (10) includes a first mode shaping section (13) which is adapted for shaping a circulating electric field coupled into the gain disk medium (11), and a second mode shaping section (14), which is adapted for shaping the circulating electric field coupled into the Kerr medium (12) independently of the electric field shaping in the first mode shaping section (13). Furthermore, a method of generating laser pulses (1) using a laser resonator (10) with a gain disk medium (11) and a Kerr medium (12) is described.