Ti:sapphire presents unequaled tuning properties. However, because of a short lifetime, the energy cannot be stored in ${\mathrm{Ti}}^{3+}$ upper level, which makes this gain medium difficult to pump. Hence, the size, price, and complexity of femtosecond laser chains are partially driven by their pump source. We present a novel concept to pump Ti:sapphire, based on light-emitting diodes (LEDs), that gathers ruggedness, compactness, simplicity, and low price. By combining LEDs and a Ce:LuAG luminescent concentrator, we report the first LED-pumped Ti:sapphire laser, to the best of our knowledge. With 2240 blue LEDs (at 450 nm) in pulsed regime (10 Hz, 15 μs), the pump module has a maximum emission at 530 nm and delivers up to 20.9 mJ with an irradiance of $9.9\mathrm{kW}/{\mathrm{cm}}^2$. This low-cost and compact pump system, among the brightest incoherent sources ever developed, enables laser emission in Ti:sapphire (32 μJ at 790 nm). The tunability of the laser is demonstrated between 755 and 845 nm. The double-pass small signal gain in the cavity is numerically simulated and measured to reach 1.066.

中文翻译：

---

发光二极管：Ti：蓝宝石泵浦的新范例

Ti：蓝宝石呈现出无与伦比的调音特性。但是，由于使用寿命短，无法将能量存储在${钛}^{3+}$较高的水平，这使得该增益介质难以泵浦。因此，飞秒激光链的尺寸，价格和复杂性部分受其泵浦源驱动。我们提出了一种新颖的概念：基于发光二极管（LED）来泵浦Ti：蓝宝石，它具有坚固性，紧凑性，简单性和低廉的价格。通过结合使用LED和Ce：LuAG发光集中器，我们据了解已报道了第一台LED泵浦的Ti：蓝宝石激光器。泵浦模块具有2240个蓝光LED（在450 nm处）（在450 Hz时）（10 Hz，15μs），在530 nm处具有最大发射，并在20.9 mJ的辐射下达到20.9 mJ$9.9\mathrm{千瓦}/{\mathrm{厘米}}^{\mathrm{2个}}$。这种低成本，紧凑的泵浦系统是有史以来最亮的非相干光源之一，可实现Ti：蓝宝石（在790 nm波长下为32μJ）的激光发射。激光的可调性在755至845 nm之间显示。数值模拟腔中的双通小信号增益，并测量得出其达到1.066。