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Journal of Zhejiang University SCIENCE A
ISSN 1673-565X(Print), 1862-1775(Online), Monthly
2015 Vol.16 No.4 P.326-334
SESAM fabrication errors and its influence on ultrafast laser cavity design
Abstract: During mode-locked ultrafast laser experiments, we find that semiconductor saturable absorber mirrors (SESAMs) from the same manufacturing process may, from batch to batch, show different working ranges: pure Q-switching, Q-switched mode-locking, and continuous wave (CW) mode-locking. This is because, in high-volume wafer-scale fabrication, there is typically an estimated 1% error for high-quality molecular beam epitaxy (MBE) growth, which introduces a variation in the parameters of an individual SESAM. In this paper, we will analyze how that 1% error in layer thickness influences the behaviour of SESAMs in three different structures: resonant SESAM, anti-resonant SESAM, and enhanced SESAM. Furthermore, the characteristics of the SESAM will affect the mode-locking dynamic behavior of ultrafast solid state lasers. In the worst case, a SESAM with a fabrication error may prevent the laser cavity from mode-locking. Proper laser cavity design can help to reduce the impact of SESAM fabrication errors on laser performance and maintain the laser in the CW mode-locking range.
Key words: Semiconductor saturable absorber mirror (SESAM), Ultrafast laser, Fabrication error, Design criteria
创新点:从激光器腔型设计方案出发,采用不同曲率镜,调整激光腔中激光晶体及可饱和吸收镜上的光斑半径大小比值,解决SESAM制造误差对激光器输出的影响。
方法:采用传递矩阵法计算SESAM半导体膜层厚度对其光学性能的影响。对于不同的SESAM设计,影响大小不同(表1)。
结论:通过改变腔内曲率镜M1,M2和M3的曲率值大小以及腔的长度值,可以减弱SESAM制造误差对飞秒激光器输出的影响,实现对所有SESAM的连续锁模。
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DOI:
10.1631/jzus.A1500030
CLC number:
TN248.1
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On-line Access:
2024-08-27
Received:
2023-10-17
Revision Accepted:
2024-05-08
Crosschecked:
2015-03-25