The efficiency and bandwidth of an optical absorbing material, especially for the promising two-dimensional transition metal dichalcogenides (TMDCs) are critical to underpin advances in photonic and optoelectronic devices. In this work, we present a general method to manipulate the bandwidth of an absorber with high efficiency through coupling with the quasi-bound states in the continuum (quasi-BIC). We demonstrate this strategy by taking absorbing material monolayer TMDC coupled with the lossless symmetry-broken photonic crystal (PhC) slab. An optimal-efficiency TMDC-based absorber with over three orders of magnitude of bandwidth adjustment is realized, by simultaneously adjusting the structure asymmetry parameter of PhC slab and the locations of monolayer TMDC in the structure. Interestingly, the absorption bandwidth is tailored quadratically with the asymmetry parameter, which derived from the powerful physics of bound state in the continuum (BIC) in radiation engineering. Moreover, a superior-performance optical refractive index sensor is further designed. We demonstrate that our proposed method based on quasi-BIC structure can also effectively govern the sensing performance. Present work not only provides further insight into BIC physics, but also offers a promising strategy of smart engineering in active optical devices with the properties on demand.

光吸收材料的效率和带宽，特别是对于有前途的二维过渡金属二硫属化物 (TMDC)，对于支持光子和光电器件的进步至关重要。在这项工作中，我们提出了一种通过与连续介质中的准束缚态（准 BIC）耦合来高效操纵吸收体带宽的通用方法。我们通过将吸收材料单层 TMDC 与无损对称破坏光子晶体 (PhC) 板相结合来证明这一策略。通过同时调整PhC板的结构不对称参数和单层TMDC在结构中的位置，实现了具有三个数量级以上带宽调整的最优效率TMDC基吸收体。有趣的是，吸收带宽与不对称参数进行二次定制，该参数源自辐射工程中强大的连续介质中束缚态物理 (BIC)。此外，进一步设计了性能优越的光学折射率传感器。我们证明了我们提出的基于准 BIC 结构的方法也可以有效地控制传感性能。目前的工作不仅提供了对 BIC 物理学的进一步见解，而且还为具有按需特性的有源光学器件的智能工程提供了有前途的策略。我们证明了我们提出的基于准 BIC 结构的方法也可以有效地控制传感性能。目前的工作不仅提供了对 BIC 物理学的进一步见解，而且还为具有按需特性的有源光学器件的智能工程提供了有前途的策略。我们证明了我们提出的基于准 BIC 结构的方法也可以有效地控制传感性能。目前的工作不仅提供了对 BIC 物理学的进一步见解，而且还为具有按需特性的有源光学器件的智能工程提供了有前景的策略。