Characterization of optomechanical modes in multilayer stack of graphene sheets

Mohammad Mahdi Salary, Sandeep Inampudi and Hossein Mosallaei

Graphene, a two-dimensional (2D) crystalline material exhibits unique electronic, optical, and mechanical properties which makes it a promising candidate for optomechanical and optoelectronic devices. The giant plasmonic activity of graphene sheets enables low-dimensional confinement of light and enhanced light–matter interaction leading to significant enhancement of optical forces which may give rise to large mechanical deformations on account of ultralow mass density and flexibility of graphene. The multilayer stack and heterostructures of 2D materials provide access to a spectrum of guided modes which can be used to tailor the optical forces and mechanical states of graphene sheets. Here, we study the optical forces arising from the coupling of guided modes in layered structures of graphene sheets. We obtain the mechanical deformation states corresponding to each guided mode and demonstrate that the optical forces can be adjusted by changing the interlayer spacing as well as the chemical potential of graphene layers. Our results can be used for various designs of graphene-based optomechanical devices.

DOI

Laser-assisted biofabrication in tissue engineering and regenerative medicine

Sangmo Koo, Samantha M. Santoni, Bruce Z. Gao, Costas P. Grigoropoulos and Zhen Ma

Controlling the spatial arrangement of biomaterials and living cells provides the foundation for fabricating complex biological systems. Such level of spatial resolution (less than 10 µm) is difficult to be obtained through conventional cell processing techniques, which lack the precision, reproducibility, automation, and speed required for the rapid fabrication of engineered tissue constructs. Recently, laser-assisted biofabrication techniques are being intensively developed with the use of computer-aided processes for patterning and assembling both living and nonliving materials with prescribed 2D or 3D organization. In this review, we discuss laser-assisted fabrication methods, including laser tweezers, multi-photon polymerization, laser-induced forward transfer (LIFT), matrix assisted pulsed laser evaporation (MAPLE), and laser ablation as well as their applications in biological science and biomedical engineering. These advanced technologies enable the precise manipulation of in vitro cellular microenvironments and the ability to engineer functional tissue constructs with high complexity and heterogeneity, which serve in regenerative medicine, pharmacology, and basic cell biology studies.

DOI