Persistent Hole Burning and Femtosecond Photon Echo Using Diode Laser

1. 首次实现了连续波多模二极管激光器和超发光二极管的非相干光光子回波。持续烧孔作为未来多波长光存储器的潜力一直受到人们的关注。我们在传统二极管激光器的波长区域（780 nm附近）发现了一种高效的持续烧孔材料HITC/PVA。通过改变二极管激光器注入电流的波长扫描，我们以10毫秒的时间分辨率观察了HITC/PVA中持续空穴的时间演变。我们发现，htc /PVA的持久孔在一次燃烧时可以被证明超过1000次。利用上述方法，我们观察了HITC/PVA.6中持续空穴的光谱扩散和自填充过程。我们观察了HITC/PVA（聚合物寄主）和HITC/EtOH（单体寄主）两种样品中持久孔的时间演化，并假设寄主中的两个能级系统在空间上呈分形分布来解释这一行为。该理论给出了光子回波衰减曲线、持续空穴形状和温度对空穴宽度的依赖关系，其依赖于分形维数D。通过与实验的比较，我们得到了HITC/PVA的D=2.1 2.3， HITC/EtOH的D=2.7。

1. The incoherent light photon echoes by using a cw multi-mode diode laser or a superluminescent diode have been performed for the first time.2. Persistent hole burning has been attracting much attention because of its potentiality as future multi-wavelength optical memory. We found out an efficient persistent hole burning material HITC/PVA at the wavelength region of conventional diode lasers, near 780 nm.3. Using the wavelength sweep by changing the injection current into diode lasers, we observed the time evolution of the persistent hole in HITC/PVA with a temporal resolution of 10 msec.4. We found that the persistent hole in HITC/PVA can be proved more than 1000 times when it was once burnt.5. By using the methods mentioned above, we observed spectral diffusion and self-refilling process of the persistent hole in HITC/PVA.6. We observed the temporal evolution of persistent holes in two samples HITC/PVA (polymeric host) and HITC/EtOH (monomeric host), and explained the behavior by assuming that the two level systems in the host are spatially distributed like a fractal. This theory gives the photon echo decay curve, persistent hole shape and the temperature dependence of the hole width which depend on the fractal dimension D. By comparison with the experiment, we obtained D=2.1 2.3 for HITC/PVA and D=2.7 for HITC/EtOH.