In a significant development, researchers from Bengaluru have shown for the first time that how a metal interacts with light can be actively tuned by applying mechanical strain.
This finding challenges a long-held assumption in physics that the optical properties of metals are unchangeable. It opens new pathways for building reconfigurable optical devices compatible with standard semiconductor manufacturing.
Utilizing ultrathin titanium nitride (TiN) films, the researchers isolated the role of strain on plasmonic behavior. Two identical TiN films were compared: one was strain-free, while the other was subject to controlled tensile strain.
The strained TiN film exhibited a blue shift of 0.30–0.45 electron volts in its plasmon resonance, indicating that strain significantly modifies the metal's electronic response.