Efficient Cherenkov emission of broadband terahertz radiation from an ultrashort laser pulse in a sandwich structure with nonlinear core
Efficient Cherenkov emission of broadband terahertz radiation from an ultrashort laser pulse in a sandwich structure with nonlinear core
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DOI：
10.1063/1.3005987
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发表时间：
2008-11
影响因子：
3.2
通讯作者：
S. Bodrov;M. Bakunov;M. Hangyo
中科院分区：
文献类型：
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作者：
S. Bodrov;M. Bakunov;M. Hangyo
提出了一种利用飞秒激光脉冲在平面三明治结构中传输高效产生宽带太赫兹辐射的方案。该结构由一个薄的非线性核心组成，外加棱镜，棱镜由低太赫兹吸收材料制成。聚焦成线的激光脉冲以漏模或波导模的形式在核心中传播，并在包层中发射切伦科夫楔形太赫兹波。我们发展了一种描述这种结构中太赫兹产生的理论，并计算了产生太赫兹场的空间分布、能谱和光-太赫兹转换效率。理论计算表明，在长1 cm、宽1 cm的Si-LiNbO_3-Si夹层结构中，用脉冲宽度为100fs的8.5μJ钛宝石激光泵浦，具有20μm厚的非线性层，其转换效率可达几个百分点。
A scheme for efficient generation of broadband terahertz radiation by a femtosecond laser pulse propagating in a planar sandwichlike structure is proposed. The structure consists of a thin nonlinear core cladded with prisms made of a material with low terahertz absorption. The focused into a line laser pulse propagates in the core as a leaky or waveguide mode and emits Cherenkov wedge of terahertz waves in the cladding. We developed a theory that describes terahertz generation in such a structure and calculated spatial distribution of the generated terahertz field, its energy spectrum and optical-to-terahertz conversion efficiency. The developed theory predicts the conversion efficiency of up to several percent in a 1 cm long and 1 cm wide Si–LiNbO3–Si sandwich structure with a 20 μm thick nonlinear layer pumped by 8.5 μJ Ti:sapphire laser with pulse duration of 100 fs.