Ultrafast all-optical control has been a subject of wide-spread attention as a method of manipulating optical fields using light excitation on extremely short time scales. As a fundamental form of ultrafast all-optical control, all-optical switching has achieved sub-picosecond switch speeds in the visible, infrared, and terahertz spectral regions. However, due to the lack of suitable materials, ultrafast all-optical control in the ultraviolet range remains in its early stages. We demonstrate sub-picosecond all-optical switching in the ultraviolet wavelength by designing a Si3N4-ITO Fabry–Pérot resonance aligns with the edge of the interband transition region of ITO. The response time of 500 fs achieved at a pump fluence as low as 0.17 mJ/cm2. Notably, unlike conventional binary switches (0, 1), this biphasic all-optical switch enables the modulation of optical intensity with positive, zero, and negative ΔR/R (0, 1, −1) at the same wavelength, all achieved with a switching speed of 680 fs at a pump fluence of 0.45 mJ/cm2. This work establishing a new pathway for all-optical control in the ultraviolet spectrum, the biphasic switch provides an extra degree of freedom for all-optical modulation.

中文翻译：

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紫外波段亚皮秒双相超快全光切换


超快全光控制作为一种在极短的时间尺度上使用光激发操纵光场的方法，一直是广泛关注的主题。作为超快全光控制的基本形式，全光开关在可见光、红外和太赫兹光谱区域实现了亚皮秒级开关速度。然而，由于缺乏合适的材料，紫外范围内的超快全光学控制仍处于早期阶段。我们通过设计 Si3N4-ITO 法布里-佩罗共振与 ITO 带间过渡区的边缘对齐，展示了紫外波长下的亚皮秒全光切换。在泵通量低至 0.17 mJ/cm2 时实现了 500 fs 的响应时间。值得注意的是，与传统的二进制开关 （0， 1） 不同，这种双相全光开关可以在相同波长下以正、零和负 ΔR/R （0， 1， −1） 调制光强度，所有这些都以 680 fs 的开关速度实现，泵浦通量为 0.45 mJ/cm2。这项工作为紫外光谱中的全光控制建立了一条新的途径，双相开关为全光调制提供了额外的自由度。