Gürel Kutan, Wittwer Valentin J, Hakobyan Sargis, Schilt Stéphane, Südmeyer Thomas
Opt Lett. 2017 Mar 15;42(6):1035-1038. doi: 10.1364/OL.42.001035.
We demonstrate the first diode-pumped Ti:sapphire laser frequency comb. It is pumped by two green laser diodes with a total pump power of 3 W. The Ti:sapphire laser generates 250 mW of average output power in 61-fs pulses at a repetition rate of 216 MHz. We generated an octave-spanning supercontinuum spectrum in a photonic-crystal fiber and detected the carrier envelope offset (CEO) frequency in a standard f-to-2f interferometer setup. We stabilized the CEO-frequency through direct current modulation of one of the green pump diodes with a feedback bandwidth of 55 kHz limited by the pump diode driver used in this experiment. We achieved a reduction of the CEO phase noise power spectral density by 140 dB at 1 Hz offset frequency. An advantage of diode pumping is the ability for high-bandwidth modulation of the pump power via direct current modulation. After this experiment, we studied the modulation capabilities and noise properties of green pump laser diodes with improved driver electronics. The current-to-output-power modulation transfer function shows a bandwidth larger than 1 MHz, which should be sufficient to fully exploit the modulation bandwidth of the Ti:sapphire gain for CEO stabilization in future experiments.
我们展示了首个二极管泵浦钛宝石激光频率梳。它由两个绿色激光二极管泵浦，总泵浦功率为3瓦。钛宝石激光器在重复频率为216兆赫兹的情况下，以61飞秒脉冲产生250毫瓦的平均输出功率。我们在光子晶体光纤中产生了一个倍频程超连续谱，并在标准的f - 2f干涉仪装置中检测了载波包络偏移（CEO）频率。我们通过对其中一个绿色泵浦二极管进行直流调制来稳定CEO频率，该调制的反馈带宽受本实验中使用的泵浦二极管驱动器限制，为55千赫兹。在1赫兹偏移频率下，我们实现了将CEO相位噪声功率谱密度降低140分贝。二极管泵浦的一个优点是能够通过直流调制对泵浦功率进行高带宽调制。在此实验之后，我们利用改进的驱动电子设备研究了绿色泵浦激光二极管的调制能力和噪声特性。电流 - 输出功率调制传递函数显示带宽大于1兆赫兹，这对于在未来实验中充分利用钛宝石增益的调制带宽来稳定CEO应该是足够的。
