Nanolithography with ultra-short laser pulses

光刻技术是基础研究和广泛应用的关键技术。它通常在半导体行业和摩尔定律的背景下进行讨论：该行业的能力是每三年将芯片上的晶体管数量增加四倍。为了跟上快速“缩小”的晶体管尺寸，人们积极探索替代的光刻技术，其中包括原子纳米光刻。与使用单色光束的传统光学光刻相比，原子光刻利用在沉积在固体表面上之前由光场操纵的原子束。在这两种情况下，分辨率由衍射极限决定，因此由相应光束的波长决定。虽然光波长在几百纳米的范围内，但原子物质波的波长以皮米为单位测量。因此，特别有吸引力的是使用原子光学来推动纳米光刻的边界，并在纳米纤维中达到更短的长度尺度。在这里，我建议建立一个创新的计划，原子纳米纤维与超短激光脉冲。该计划将有两个主要目标。首先，我们将开发利用脉冲光场控制原子和分子运动的技术。其次，新技术将用于解决连续波激光源原子光刻的两个主要缺点：1）其适用性有限，只能选择一小部分原子，2）其固有的局限性仅限于周期性纳米结构。基于原子与高功率飞秒脉冲的非共振相互作用，如多光子电离，该方法将被扩展到甚至复杂的分子。短脉冲的宽光谱带宽和它们在空间中的紧密定位将使分子分布的控制超越目前证明的周期性调制。新的实验技术将连接超快光学，原子物理学和纳米科学，激发一个全新的研究方向，并吸引学生到这个迷人的跨学科领域。

Lithography is a key technology enabling progress both in fundamental research and in widespread applications. It is usually discussed in the context of the semiconductor industry and Moore's law: the industry's ability to quadruple the number of transistors on a chip every three years. In an effort to keep up with quickly "shrinking" transistor size, alternative lithographic techniques are actively explored, and among them - atom nanolithography. In contrast to conventional optical lithography, which uses monochromatic beam of light, atom lithography utilizes the beam of atoms which is manipulated by optical fields before being deposited on a solid surface. In both cases the resolution is dictated by the diffraction limit, and therefore by wavelength of the corresponding beam. While optical wavelengths are in the range of a few hundred nanometers, the wavelength of a matter wave of atoms is measured in picometers. It is therefore particularly attractive to use atom optics for pushing the boundaries of nanolithography and reaching much shorter length scales in nanofabrication. Here I propose to establish an innovative program on atom nanofabrication with ultra-short laser pulses. This program will have two main objectives. First, we will develop the technology of controlling atomic and molecular motion with pulsed optical fields. And second, the new technique will be applied to tackle two major shortcomings of atom lithography with continuous-wave laser sources: 1) its limited applicability to only a small selection of atoms, and 2) its inherent restriction to only periodic nanostructures. Based on non-resonant interaction of atoms with high-power femtosecond pulses, such as multiphoton ionization, the proposed method will be extended to even complex molecules. Broad spectral bandwidth of short pulses and their tight localization in space will enable control of molecular distribution beyond currently demonstrated periodic modulation. The new experimental technique will bridge ultrafast optics, atomic physics and nanoscience, stimulating a whole new direction of research, and attracting students to this fascinating interdisciplinary field.