Conventional ways of confining charges in semiconductors employ advanced lithographic and crystal-growth techniques. The construction of micro/nano-scale structures is also essential for manipulating spins. However, existing techniques are not always flexible enough to control spins in appropriate positions and timings. Here we report an alternative mechanism, which enables us to design temporal and reconfigurable low-dimensional potentials. The formation of photo-induced potential dimples is deduced from time and spatially-resolved Kerr rotation measurements performed on a GaAs quantum well. Two-dimensional images of spin distributions reveal that the photo-injected electron spins in a small area illuminated by a pump light survive for a time that is two orders of magnitude longer than typical recombination lifetimes. The Kerr rotation dependence on the pump laser conditions implies that the temporally generated dimple-shaped potential profile induced by remote charges effectively confines the electrons and enhances the spin lifetime determined by fluctuating spin-orbit effective magnetic fields.

限制半导体中电荷的常规方法采用了先进的光刻和晶体生长技术。微观/纳米尺度结构的构造对于操纵自旋也是必不可少的。但是，现有技术并不总是具有足够的灵活性以控制适当位置和定时的旋转。在这里，我们报告了一种替代机制，该机制使我们能够设计时间性和可重构性的低维电势。根据在GaAs量子阱上进行的时间分辨和空间分辨的Kerr旋转测量，可以推断出光诱导的潜在凹坑的形成。自旋分布的二维图像显示，在由泵浦光照射的小区域内，光注入电子自旋的存活时间比典型的复合寿命长两个数量级。