Laser Tuning in van der Waals Crystals.

The great progress that optoelectronic technologies have achieved in van der Waals crystals promises the development of next-generation two-dimensional (2D) integrated optoelectronic systems (IOSs). Here, relying on the anomalous avoidance of pump-light absorption, the harvest of extremely strong Raman scattering, and the achievement of polarization inheritance by the designed optical geometry, we realized laser wavelength tuning with ultrahigh precision (0.01 nm/25 K) in layered MoS2 and WS2 by adjusting the temperature. Our results offer a potential approach for 2D laser tuning, while also building a substantial theoretical foundation, which might be of use in developing future wavelength-division-multiplexing technology in 2D IOSs.