Abstract
The recent advent of van der Waals (vdW) crystals are considered as a new class of material for optoelectronics or photonics applications, as they have a wide range of optical band gap energies and electrical transport properties. Furthermore, due to the nature of vdW interactions, these vdW materials can be transferred onto different substrates, making them a promising candidate for integrated photonics applications. Here, we will exploit these unique properties and describe how to realize ultrathin and integrable light sources, based on photonic crystal cavities integrated van der Waals light emitters. Our demonstrated device can be operated at room temperature with fast modulation speed and enhanced emission intensity. Additionally, we will show ultrathin (∼0.14 λ) van der Waals metalenses, which not only can exhibit near diffraction-limited focusing and imaging, but also can be transferred onto flexible substrates to show strain- induced tunable focusing.