NTT Basic Research Laboratories, 3-1 Morinosato Wakamiya, Atsugi, Kanagawa, 243-0198, Japan.
Department of Physics, Graduate School of Engineering, Yokohama National University, 79-5 Tokiwadai, Hodogaya, Yokohama, 240-8501, Japan.
Nat Commun. 2018 Apr 18;9(1):1468. doi: 10.1038/s41467-018-03885-7.
Lightwave-field-induced ultrafast electric dipole oscillation is promising for realizing petahertz (10 Hz: PHz) signal processing in the future. In building the ultrahigh-clock-rate logic operation system, one of the major challenges will be petahertz electron manipulation accompanied with multiple frequencies. Here we study multi-petahertz interference with electronic dipole oscillations in alumina with chromium dopant (Cr:AlO). An intense near-infrared lightwave-field induces multiple electric inter-band polarizations, which are characterized by Fourier transform extreme ultraviolet attosecond spectroscopy. The interference results from the superposition state of periodic dipole oscillations of 667 to 383 attosecond (frequency of 1.5 to 2.6 PHz) measured by direct time-dependent spectroscopy and consists of various modulations on attosecond time scale through individual electron dephasing times of the Cr donor-like and AlO conduction band states. The results indicate the possible manipulation of petahertz interference signal with multiple dipole oscillations using material band engineering and such a control will contribute to the study of ultrahigh-speed signal operation.
光波场诱导的超快电偶极子振荡有望在未来实现皮赫兹（10 Hz：PHz）信号处理。在构建超高时钟速率逻辑运算系统时，主要挑战之一将是皮赫兹电子与多个频率的操纵。在这里，我们研究了掺铬氧化铝（Cr：AlO）中的多皮赫兹干涉与电子偶极子振荡。强近红外光波场诱导了多个电带间极化，这通过傅里叶变换极端紫外阿秒光谱进行了特征化。干涉结果来自通过直接时间相关光谱测量的 667 到 383 阿秒（1.5 到 2.6 PHz 的频率）的周期性偶极子振荡的叠加态，并且包括通过 Cr 类施主和 AlO 传导带状态的各个电子去相位时间的阿秒时间尺度上的各种调制。结果表明，使用材料能带工程可以对多偶极子振荡的皮赫兹干涉信号进行可能的操纵，这种控制将有助于超高速度信号操作的研究。
