We present a thorough characterization of a red-emitting mode-locked semiconductor disk laser producing the first stable fundamental mode-locked pulse train in the red spectral range. The achievable temporal FWHM pulse length of the Lorentzian-shaped pulses is just below 3 which represents the shortest pulses obtained in a fully-resonant absorber and gain structure design. We also include an intracavity birefringent filter to stabilize and tune the emission wavelength between and . This, in combination with a real-time sampling of the emitted pulse train, allows us to distinguish three regimes according to their round-trip dynamics. The first regime resembles stable fundamental mode locking and is observed for wavelengths below while for an emission wavelength of the continuous wave regime is observed. These two operating regimes enclose the dual-pulse mode locking regime appearing between and . This regime is characterized by an energy exchange between the individual pulses of the dual-pulse mode locking regime and we clearly relate the side-peaks in the radio frequency spectrum to the dual-pulse energy-exchange frequency and the temporal interpulse spacing to the individual arm lengths of the gain-folded external cavity. Overall, we attribute these different operating regimes to near-bandgap operation of the SESAM which allows for dispersion of saturation fluence and modulation depth.

中文翻译：

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发红光 VECSEL 的稳定基波和双脉冲锁模

我们对红色发射锁模半导体盘式激光器进行了全面表征，该激光器在红色光谱范围内产生了第一个稳定的基本锁模脉冲序列。洛伦兹形脉冲的可实现时间 FWHM 脉冲长度略低于 3，这代表在全谐振吸收器和增益结构设计中获得的最短脉冲。我们还包括一个腔内双折射滤光片，以稳定和调整 和 之间的发射波长。这与发射脉冲序列的实时采样相结合，使我们能够根据往返动力学区分三种状态。第一种状态类似于稳定的基本锁模，并且观察到以下波长，而观察到连续波状态的发射波长。这两个工作机制包含出现在 和 之间的双脉冲锁模机制。这种机制的特点是双脉冲锁模机制的单个脉冲之间的能量交换，我们清楚地将射频频谱中的侧峰与双脉冲能量交换频率和时间脉冲间隔与个体相关联。增益折叠外腔的臂长。总体而言，我们将这些不同的操作机制归因于 SESAM 的近带隙操作，这允许饱和注量和调制深度的分散。这种机制的特点是双脉冲锁模机制的单个脉冲之间的能量交换，我们清楚地将射频频谱中的侧峰与双脉冲能量交换频率和时间脉冲间隔与个体相关联。增益折叠外腔的臂长。总体而言，我们将这些不同的操作机制归因于 SESAM 的近带隙操作，这允许饱和注量和调制深度的分散。这种机制的特点是双脉冲锁模机制的单个脉冲之间的能量交换，我们清楚地将射频频谱中的侧峰与双脉冲能量交换频率和时间脉冲间隔与个体相关联。增益折叠外腔的臂长。总体而言，我们将这些不同的操作机制归因于 SESAM 的近带隙操作，这允许饱和注量和调制深度的分散。