Ultrashort Pulse Propagation and Amplification in New Cr-Doped LiSAF and LiCAF Solid State Laser Materials

随着掺铬LiSAF和掺铬LiCAF激光材料的发展，为强、超短激光脉冲技术及其应用开辟了一条新的机遇之路。这些材料与其他材料不同，它们展示了产生超强、超短激光脉冲所需的固体激光材料的最吸引人的特性。它们具有高的增益和能量存储特性、良好的光学特性、高的损伤阈值，并且可以大尺寸生长。此外，它们独特地结合了长荧光寿命(LiSAF为70us，LiCAF为130us)和已知的最宽光谱发射带宽(LiSAF为220 nm)，首次实现了高增益的放大，采用闪光灯泵浦、大直径、固态激光模块的超短(100fs)脉冲。这将对未来超短、高强度激光技术在实验室x射线激光、亚皮秒x射线研究和粒子加速中的应用具有重要意义。我们将对这两种材料用作超短激光脉冲高增益放大器的所有物理性质进行全面的研究。这将包括全面检查与宽带脉冲放大有关的掺铬LiSAF和LiCAF的基本光谱和原子性质，它们放大短脉冲的能力，啁啾脉冲放大(CPA)提取能量的有效性，以及那些影响它们在大口径、多段阵列(MSA)放大器中使用的材料特性。因此，这项研究将解决将这些新材料纳入主要激光放大介质所需的所有问题。有了这项研究产生的数据，在未来的工作中，我们将能够向前迈进，建造能够在低于100秒的时间内发射数十焦耳、也许数百焦耳、可聚焦到大于1020W/cm2的强度的激光器。

A new avenue of opportunity in the field of intense, ultrashort laser pulse technology and its applications has opened as a result of the development of the laser materials Cr-doped LiSAF and Cr-doped LiCAF. These materials, like no others yet developed, display the most attractive characteristics of a solid state laser material required for the generation of ultra-intense, ultrashort laser pulses. They have high gain and energy storage properties, good optical properties, a high damage threshold and can be grown in large sizes. Moreover, they uniquely combine long fluorescence lifetimes ( 70 us for LiSAF and 130 us for LiCAF) and the broadest spectral emission bandwith known (220nm for LiSAF), making possible, for the first time, the amplification with high gain, of ultrashort ( 100fs) pulses with flashlamp-pumped, large diameter, solid state laser modules. The implications will be considerable for future applications of ultrashort, high intensity laser technology, in the development of laboratory x-ray lasers, sub-picosecond x-ray studies, and particle acceleration. We will make a comprehensive investigation of all the physical properties of these two materials associated with their use as high gain amplifiers of ultrashort laser pulses. This will include a full examination of the basic spectral and atomic properties of Cr-doped LiSAF and LiCAF pertaining to broadband pulse amplification, their capacity to amplify short pulses, the effectiveness with which chirped pulse amplification (CPA) can extract energy, and those material properties affecting their use in wide aperture, multi-segmented array (MSA) amplifiers. This study will therefore address all the issues necessary to incorporate these new materials as a major laser amplifier medium. Armed with data produced by this study, we will then be able, in future work, to move forward towards the construction of lasers capable of emitting tens, perhaps hundreds of joules in times of less than 100fs, focusable to intensities greater than 1020W/cm2.