MXenes for nanophotonic and metamaterial devices (Conference Presentation)

MXenes are a recently discovered family of two-dimensional nanomaterials formed of transition metal carbides and carbon nitrides with the general chemical form Mn+1XnTx, where ‘M’ is a transitional metal, ‘X’ is either C or N, and ‘T’ represents a surface functional group (O, -OH or -F). MXenes are derived from layered ternary carbides and nitrides known as MAX (Mn+1AXn) phases by selective chemical etching of the ‘A’ layers and addition of functional groups ‘T’. In our work, we focus on one of the most well studied MXene, titanium carbide (Ti3C2Tx). Single to few layer flakes of Ti3C2Tx (in a solution dispersed form) are used to create a continuous film on a desired substrate by using spin coating technique. Losses inherent to the bulk MXene and existence of strong localized SP resonances in Ti3C2Tx disks/pillar-like nanostructures at near-IR frequencies are utilized to design an efficient broadband absorber. For Ti3C2Tx MXene disk array sitting on a bilayer stack of Au/Al2O3, high efficiency (>90%) absorption across visible to near-IR frequencies (bandwidth ~1.55 μm), is observed experimentally. We also experimentally study random lasing behavior in a metamaterial constructed by randomly dispersing single layer nanosheets of Ti3C2Tx into a gain medium (rhodamine 101, R101). Sharp lasing peaks are observed when the pump energy reaches the threshold value of ~ 0.70 μJ/pulse. This active metamaterial holds a great potential to achieve tunable random lasing by changing the optical properties of Ti3C2Tx flakes.