Cascaded third-harmonic generation approaching full efficiency through an unconventional pathway
Cascaded third-harmonic generation approaching full efficiency through an unconventional pathway
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级联三次谐波生成通过非常规途径接近最高效率
DOI：
10.1117/12.2651978
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Moses, Jeffrey
中科院分区：
文献类型：
--
作者：
Castanheira, Nuno V.;Flemens, Noah;Moses, Jeffrey
三次谐波产生（THG）的多个二次非线性过程的同时相位匹配在一个单一的晶体已被研究以前的理论和实验，实现适度的转换效率。与串联使用二次谐波产生（SHG）和和频产生（SFG）级的常见实践相反，并行执行这些过程导致窄的材料参数范围，其中即使在完美相位匹配的条件下，能量到三次谐波的传递也可以是完全有效的。这在很大程度上是由于转换动力学中存在反向转换，这限制了时空非均匀光束的效率。在这里，我们展示了一种非常规的三倍频方法，其中基波首先通过级联的倍频进行四倍频，然后下变频为三次谐波。当三个相关的相位匹配条件同时满足时，我们发现能量被鲁棒有效地从基波转移到三次谐波，并抑制了反向转换。这是最近在杂化参量放大中观察到的杂化非线性光学过程中出现的收敛动力学行为的一个例子。这些动力学可在对应于常见非线性晶体的宽参数范围内实现。利用时空数值模拟方法，我们发现在可实现的单片取向图形GaAs器件中，具有高斯时空分布、波长为10 μm的25 ps CO2激光脉冲可以被转换成其三次谐波，转换效率超过80%。高性能可实现的域极化KTP和LNB设备也进行了研究。
Third harmonic generation (THG) achieved by the simultaneous phase matching of multiple quadratic nonlinear processes in a single crystal has been studied previously both theoretically and experimentally, achieving modest conversion efficiencies. As opposed to the common practice of using second harmonic generation (SHG) and sum frequency generation (SFG) stages in series, performing these processes in parallel results in a narrow material parameter range in which the transfer of energy to the third harmonic can be fully efficient, even under conditions of perfect phase matching. This is largely due to the presence of back-conversion in the conversion dynamics, which limits the efficiency for spatio-temporally non-uniform beams. Here we demonstrate an unconventional method of THG where the fundamental wave is first frequency-quadrupled through cascaded SHG before being down-converted to the third harmonic. When the three associated phase matching conditions are met simultaneously, we find that energy is transferred robustly and efficiently from the fundamental wave to the third harmonic with inhibited back-conversion. This is an example of convergent dynamical behavior emerging from hybridized nonlinear optical processes as recently observed in hybridized parametric amplification. These dynamics are achievable over a broad parameter range that correspond to common nonlinear crystals. Using a spatio-temporal numerical investigation, we find that 25-ps CO2laser pulses with Gaussian spatio-temporal profiles and 10-μm wavelength can be converted to their third harmonic with over 80% conversion efficiency in a realizable monolithic orientation-patterned GaAs device. High performance realizable domain-poled KTP and LNB devices are also investigated.
准周期极化 KTiOPO4 晶体中的高效级联三次谐波产生
影响因子：
1.6
作者：
Augustin Vernay;Lucas Bonnet;V. Boutou;Sivan Trajtenberg‐Mills;A. Arie;B. Boulanger
通讯作者：
B. Boulanger
准相位匹配和失配配置中高效级联三次谐波产生的理论研究
DOI：
--
发表时间：
2003
期刊：
影响因子：
--
作者：
Yiqiang Qin;Yong‐yuan Zhu;Chao Zhang;N. Ming
通讯作者：
N. Ming