Microwatts continuous-wave pumped second harmonic generation in few-and mono-layer GaSe

• 来源期刊: 光：科学与应用（英文版）
• 关键词: gallium selenide photonic crystal cavity second harmonic generation two-dimensional materials
• 年，卷（期）: 2018,（1）
• 页码范围: 79-84
• 页数: 6页
• 语种: 英文
• DOI: 10.1038/lsa.2017.126

摘要

We demonstrate the first achievement of continuous-wave (CW) pumped second harmonic generation (SHG) in few-and monolayer gallium selenide (GaSe) flakes,which are coated on silicon photonic crystal (PC) cavities.Because of ultrahigh second order nonlinearity of the two-dimensional (2D) GaSe and localized resonant mode in the PC cavity,SHG's pump power is greatly reduced to microwatts.In a nine-layer GaSe coated PC cavity,while the optical power inside the GaSe flake is only 1.5％ of that in the silicon PC slab,the SHG in GaSe is more than 650 times stronger than the third harmonic generation in silicon slab,indicating 2D GaSe's great potentials to strengthen nonlinear processes in silicon photonics.Our study opens up a new view to expand 2D materials' optoelectronic applications in nonlinear regime and chip-integrated active devices.