An interesting property of high harmonic generation in solids is its laser polarization dependent nature which in turn provides information about the crystal and band structure of the generation medium. Here we report on the linear polarization dependence of high-order harmonic generation from a gallium arsenide crystal. Interestingly, we observe a significant evolution of the anisotropic response of above bandgap harmonics as a function of the laser intensity. We attribute this change to fundamental microscopic effects of the emission process comprising a competition between intraband and interband dynamics. This intensity dependence of the anisotropic nature of the generation process offers the possibility to drive and control the electron current along preferred directions of the crystal, and could serve as a switching technique in an integrated all-solid-state petahertz optoelectronic device.
Observation of persistent photoconductivity in bulk Gallium Arsenide and Gallium Phosphide samples at cryogenic temperatures using the Whispering Gallery mode method
Piezoelectric optomechanical platforms present one of the most promising routes towards efficient transduction of signals from the microwave to the optical frequency domains. New device architectures need to be developed in order to achieve the stringent requirements for building efficient quantum transducers. In this work, we utilize the mechanical supermode principle to improve the overall microwave to optical transduction efficiency, by fabricating Lamb wave resonators that are hybridized with the mechanical breathing modes of a rib waveguide in a suspended gallium arsenide (GaAs) photonic …
We demonstrate the simultaneous generation of second and third harmonic signals from a telecom wavelength pump in a gallium phosphide (GaP) microdisk. Using analysis of the power scaling of both the second and third harmonic outputs and calculations of nonlinear cavity mode coupling factors, we study contributions to the third harmonic signal from direct and cascaded sum frequency generation processes. We find that despite the relatively high material absorption in gallium phosphide at the third harmonic wavelength, both of these processes can be significant, with relative magnitudes that depe…
We designed, fabricated and tested gallium phosphide (GaP) nano-waveguides for second harmonic generation (SHG). We demonstrate SHG in the visible range around 655 nm using low power continuous-wave pump in the optical communication O-band. Our structures utilize modal phase matching, such that lower order eigenmodes of the pump are phase matched to higher order eigenmodes of the second harmonic. We observe phase matched SHG for different combinations of interacting modes by varying the widths of the waveguides and tuning the wavelength of the pump. The presented results contribute to the deve…
We theoretically and experimentally investigate type II second harmonic generation in III-V-on-insulator wire waveguides. We show that the propagation direction plays a crucial role and that longitudinal field components can be leveraged for robust and efficient conversion. We predict that the maximum theoretical conversion is larger than that of type I second harmonic generation for similar waveguide dimensions and reach an experimental conversion efficiency of 12 %/W, limited by the propagation loss.
Resonant metasurfaces are an attractive platform for enhancing the non-linear optical processes, such as second harmonic generation (SHG), since they can generate very large local electromagnetic fields while relaxing the phase-matching requirements. Here, we take this platform a step closer to the practical applications by demonstrating visible range, continuous wave (CW) SHG. We do so by combining the attractive material properties of gallium phosphide with engineered, high quality-factor photonic modes enabled by bound states in the continuum. For the optimum case, we obtain efficiencies ar…
We demonstrate post-fabrication target-wavelength trimming with a gallium phosphide on silicon nitride integrated photonic platform using controlled electron-beam exposure of hydrogen silsesquioxane cladding. A linear relationship between the electron-beam exposure dose and resonant wavelength red-shift enables deterministic, individual trimming of multiple devices on the same chip to within 30 pm of a single target wavelength. Second harmonic generation from telecom to near infrared at a target wavelength is shown in multiple devices with quality factors on the order of $10^4$. Post-fabricati…
Tensor-driven geometric phase in nonlinear AlGaAs metasurfaces
Université Paris Cité（巴黎西岱大学）；CNRS（法国国家科学研究中心）；Karlsruhe Institute of Technology（卡尔斯鲁厄理工学院）；Centre de Nanosciences et de Nanotechnologies, Université Paris-Saclay（巴黎萨克雷大学纳米科学和纳米技术研究中心）；University of Brescia（布雷西亚大学）
A new process to produce Orientation-Patterned Gallium Phosphide (OP-GaP) on GaAs with almost perfectly parallel domain boundaries is presented. Taking advantage of the chemical selectivity between phosphides and arsenides, OP-GaP is processed into suspended shallow-ridge waveguides. Efficient Second-Harmonic Generation from Telecom wavelengths is achieved in both Type-I and Type-II polarisation configurations. The highest observed conversion efficiency is \SI{200}{\percent\per\watt\per\centi\meter\squared}, with a bandwidth of \SI{2.67}{\nano\meter} in a \SI{1}{\milli\meter}-long waveguide. T…
利用磷化镓的集成光子电路的开发需要用于制造绝缘体上GaP器件的稳健的、可扩展的工艺。在这里，我们提出了第一个GaP光子器件的SiO $_2$。该工艺利用将GaP/Al $_x$ Ga $_{1-x}$ P/GaP异质结构直接晶片键合到Si上$_2$晶片上，随后去除GaP衬底和Al $_x$ Ga $_{1-x}$ P停止层。光子器件如光栅耦合器、波导和环形谐振器通过感应耦合等离子体反应离子蚀刻在顶部GaP器件层中图案化。制作的光栅耦合器的峰值耦合效率高达4.8dB。光学品质因数为17000，以及二次和三次谐波产生观察与环形谐振器。由于GaP的大带隙在电信波长处提供低的双光子吸收，因此通过这项工作实现的绝缘体上GaP光子器件的高产率制造对于纳米光子学中的应用特别感兴趣，其中高品质因数或低模式体积可以产生高电场强度。大的带隙还使得能够实现在可见波长下操作的集成光子器件。
