Nanomachining and Nano-Synthesis of Transparent Materials using Laser Plasma Soft X-Rays

真空紫外光、极紫外光和软X射线的光波长很短，因此可以用来以纳米级的分辨率照射材料。即使是在可见光或紫外区透明的材料也能吸收如此短波长的光，这导致了单光子过程对电子态的激发。到目前为止，只有通过短波长光照射才能实现材料的刻蚀和改性。然而，通过高功率密度的辐射去除几层表面的烧蚀还没有实现。在本工作中，我们选择了用激光产生的激光等离子体软X射线。软X射线是从用聚焦激光照射目标而产生的等离子体中发射的。与其他X射线源相比，软X射线源可以有足够的亮度。此外，它还提供了一个实用的X射线源，因为它不需要任何巨大的设备。此外，我们还研究和开发了可以有效聚焦10 nm左右的软X射线的X射线光学系统。因此，我们开发了一种用高功率密度的软X射线照射材料的装置。利用X射线辐照系统，我们在世界上首次证明了无机透明材料可以用短波长的强光照射。此外，应该注意的是，可以通过烧蚀来制造50 nm的沟槽。因此，我们展示了激光等离子体软X射线用于纳米机械加工的能力。此外，各种透明材料可以通过激光等离子体软X射线的照射来烧蚀。所得结果可应用于微型化学反应器和微型化学分析仪的制造。此外，较高的X射线源可以通过核心电子激发和高密度激发应用于材料合成。

Light in the range of vacuum ultraviolet, extreme ultraviolet and soft X-rays have short wavelengths and hence can be used to irradiate materials with resolutions in nanometer scale. Even materials which are transparent in visible or ultraviolet region can absorb light at such short wavelengths, which results in excitation of electronic states by one-photon process. So far, only etching and modification of materials have been achieved by irradiation with short-wavelength light. However, ablation, in which several layers of surfaces are removed by irradiation at high power density, have not been achieved. In the present work, we selected laser plasma soft X-rays which are generated using lasers. The soft X-rays are emitted from a plasma which is generated by irradiation of a target with focused laser light. Compared to other X-ray sources, the soft X-ray sources, the soft X-ray can be bright enough. Furthermore, it provides a practical X-ray source because it does not require any huge equipment. In addition, we have investigated and developed X-ray optics that can focus soft X-rays around 10 nm efficiently. Thus, we have developed a apparatus to irradiate materials with soft X-rays at high power densities. Using the X-ray irradiation system, we demonstrated that inorganic transparent can be irradiation with intense light at a short wavelength, for the first time in the world. Furthermore, it should be noted that trenches with of 50 nm can be fabricated by ablation. Thus, we demonstrated capability of laser plasma soft X-rays for nanomachining. In addition, a wide variety of transparent materials can be ablated by irradiation with laser plasma soft X-rays. The obtained results can be applied can be applied to fabricate micro-chemical reactors and micro-chemical analyzers. Furthermore, the higher X-rays source can be applied to material synthesis by core electron excitation and high density excitation.