コロンビア大学とミラノ工科大学の研究者らは、原子レベルの薄さの材料を用いて、レーザー光の色を変えることができるデバイス作製に成功。この微細なデバイスは、従来のカラーコンバータの数分の一の大きさで、新しい種類の超小型光回路チップの実現や量子光学の進展につながる可能性がある。 Researchers at Columbia University and Politecnico di Milano have used an atomically thin material to build a device that can change the color of laser beams. Their microscopic device—a fraction of the size of conventional color converters—may yield new kinds of ultra-small optical circuit chips and advance quantum optics.
2022-08-22 コロンビア大学
3R-MoS2の場合は、ほとんど即座に極めて大きな増強効果を確認することができた。
これは、インターネットやテレビなどの光通信に応用できる可能性を秘めた重要な機能である。
＜関連情報＞
- https://www.engineering.columbia.edu/news/microscopic-color-converters-move-small-laser-closer-reality
- https://arxiv.org/abs/2204.12618
原子層状半導体におけるコンパクトな位相整合・導波路型非線形光学の実現にむけて Towards compact phase-matched and waveguided nonlinear optics in atomically layered semiconductors
Xinyi Xu, Chiara Trovatello, Fabian Mooshammer, Yinming Shao, Shuai Zhang, Kaiyuan Yao, Dmitri N. Basov, Giulio Cerullo, P. James Schuck
arXiv
Subjects:
Optics (physics.optics); Materials Science (cond-mat.mtrl-sci)
Cite as:
arXiv:2204.12618 [physics.optics]
(or arXiv:2204.12618v1 [physics.optics] for this version)
Nonlinear frequency conversion provides essential tools for light generation, photon entanglement, and manipulation. Transition metal dichalcogenides (TMDs) possess huge nonlinear susceptibilities and 3R-stacked TMD crystals further combine broken inversion symmetry and aligned layering, representing ideal candidates to boost the nonlinear optical gain with minimal footprint. Here, we report on the efficient frequency conversion of 3R-MoS2, revealing the evolution of its exceptional second-order nonlinear processes along the ordinary (in-plane) and extraordinary (out-of-plane) directions. By measuring second harmonic generation (SHG) of 3R-MoS2 with various thickness – from monolayer (~0.65 nm) to bulk (~1 {\mu}m) – we present the first measurement of the in-plane SHG coherence length (~530 nm) at 1520 nm and achieve record nonlinear optical enhancement from a van der Waals material, >10^4 stronger than a monolayer. It is found that 3R-MoS2 slabs exhibit similar conversion efficiencies of lithium niobate, but within propagation lengths >100-fold shorter at telecom wavelengths. Furthermore, along the extraordinary axis, we achieve broadly tunable SHG from 3R-MoS2 in a waveguide geometry, revealing the coherence length in such structure for the first time. We characterize the full refractive index spectrum and quantify both birefringence components in anisotropic 3R-MoS2 crystals with near-field nano-imaging. Empowered with these data we assess the intrinsic limits of the conversion efficiency and nonlinear optical processes in 3R-MoS2 attainable in waveguide geometries. Our analysis highlights the potential of 3R-stacked TMDs for integrated photonics, providing critical parameters for designing highly efficient on-chip nonlinear optical devices including periodically poled structures, resonators, compact optical parametric oscillators and amplifiers, and optical quantum circuits.
