Free‐space super‐strong terahertz (THz) electromagnetic fields offer multifaceted capabilities for reaching extreme nonlinear THz optics. However, the lack of powerful solid‐state THz sources with single pulse energy >1 mJ is impeding the proliferation of extreme THz applications. The fundamental challenge lies in hard to achieve high efficiency due to high intensity pumping caused crystal damage, linear absorption, and nonlinear distortion induced short effective interaction length, and so on. Here, through cryogenically cooling the crystals, tailoring the pump laser spectra, chirping the pump pulses, and magnifying the laser energies, 1.4‐mJ THz pulses are successfully realized in lithium niobates under the excitation of 214‐mJ femtosecond laser pulses via tilted pulse front technique. The 800 nm‐to‐THz energy conversion efficiency reaches 0.7%, and a free‐space THz peak electric and magnetic field reaches 6.3 MV cm⁻¹ and 2.1 Tesla. Numerical simulations reproduce the experimental optimization processes. To show the capability of this super‐strong THz source, nonlinear absorption in high conductive silicon induced by strong THz electric field is demonstrated. Such a high‐energy THz source with a relatively low peak frequency is very appropriate not only for electron acceleration toward table‐top X‐ray sources but also for extreme THz science and nonlinear applications.

中文翻译：

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铌酸锂产生的1.4mJ高能太赫兹辐射

自由空间超强太赫兹（THz）电磁场为达到极端非线性THz光学器件提供了多方面的功能。但是，缺乏功能强大的固态THz源（单脉冲能量> 1 mJ）阻碍了极端THz应用的扩散。根本的挑战在于由于高强度泵浦导致晶体损坏，线性吸收以及非线性畸变引起的有效相互作用长度短等原因，难以实现高效率。在这里，通过低温冷却晶体，调整泵浦激光光谱，调频泵浦脉冲并放大激光能量，在214-mJ飞秒激光脉冲通过倾斜脉冲前沿激发下，铌酸锂中成功实现了1.4-mJ THz脉冲。技术。800 nm至THz的能量转换效率达到0。^-1和2.1特斯拉。数值模拟重现了实验优化过程。为了显示这种超强太赫兹源的能力，证明了强太赫兹电场在高导电硅中的非线性吸收。如此高峰值频率的高能量太赫兹源不仅非常适合电子向台式X射线源的加速，而且非常适合太赫兹科学和非线性应用。