Numerical Simulation of Gold Nanostructure Absorption Efficiency for Fiber-Optic Photoacoustic Generation

In many non-destructive testing and medical diagnostic applications, photoacoustic generation by optical flber is an efiective approach to meet the requirements of broad bandwidth and compact size. The energy absorption layer coated onto the flber endface plays an important role in the conversion of laser energy into heat used to excite acoustic waves. Gold nanostructures are promising solutions to be utilized as energy absorption layers due to their capability of absorbing maximum optical energy at plasmon resonant frequencies. The appropriate selection of the organization and dimensions of the gold nanostructures is the key to achieving high absorption e-ciency. Numerical modeling is an e-cient way to predict the behavior of the system as a variation of select parameters. A 3D flnite integral technique model was established to simulate the dependency of absorption e-ciency on the organization and dimensions of the gold nanospheres and nanorods. The simulation results provided practical clues to the design and fabrication of flber-optic photoacoustic generators.