Mutter Patrick, Mølster Kjell Martin, Zukauskas Andrius, Pasiskevicius Valdas, Canalias Carlota
Opt Lett. 2023 Mar 15;48(6):1534-1537. doi: 10.1364/OL.481694.
We demonstrate first-order quasi-phase-matched backward second-harmonic generation (BSHG) with an efficiency of 18.7%. This represents an increase by two orders of magnitude from earlier experiments employing higher-order quasi-phase-matching. The efficient BSHG is demonstrated in bulk periodically poled Rb:KTiOPO with a poling period of 317 nm. Using these structures, the frequency doubling in the backward direction is achieved for the fundamental wavelength of 2309 nm. Here we report on the experimental investigation of the BSHG properties such as spectral bandwidth, temperature tuning, and temperature bandwidth by employing broadband and narrowband fundamental wavelength sources. The BSHG properties are compared with those of co-propagating second harmonic generation to reveal the BSHG potential for novel applications that were proposed theoretically but have not been realized in practice so far.
我们展示了一阶准相位匹配反向二次谐波产生（BSHG），效率为18.7%。这比早期采用高阶准相位匹配的实验提高了两个数量级。在极化周期为317 nm的块状周期性极化Rb:KTiOPO中实现了高效的BSHG。利用这些结构，在2309 nm的基波波长下实现了反向倍频。在此，我们报告了通过使用宽带和窄带基波波长源对BSHG特性（如光谱带宽、温度调谐和温度带宽）进行的实验研究。将BSHG特性与同向传播二次谐波产生的特性进行比较，以揭示BSHG在理论上已提出但迄今尚未在实践中实现的新型应用中的潜力。
