Electromagnetically induced modification of metal optical properties
Abstract
This project continues our work to demonstrate how the reflection and transmission of light from a thin metal film can be externally controlled by ultrafast, few-cycle laser pulses. The physical basis of the concept follows from the explanation of reflection as a classical radiation process- Light illuminating the film induces current, which then radiates, and it is the interference between this radiation and the illuminating light that accounts for the observed strong reflection and weak transmission. We have recently shown that it is possible to externally alter the current induced by a signal beam in a thin gold film using two conditioning beams. The reflection and transmission of the signal beam is then found to be modified by the action of the conditioning beams. These beams consist of carefully controlled few-cycle optical pulses at the femtosecond (fs) time scale. The conditioning pulses partly impede the formation of current that would otherwise be driven by the signal pulses, and does so without damage to the metal. In this way, the radiation process above is partly inhibited resulting in modified reflection and transmission of the signal light; an effect we call Electromagnetically Induced Modification (EIM). The proof-of-principle experiment demonstrating EIM will be expanded in this work with the intent to advance our understanding for the physical processes involved. We will test the dependence of EIM on the spatial beam characteristics, study its behavior as the temporal character of the pulses vary, and extend the investigation to several metals. Such work will greatly fortify our understanding for EIM and definitively test the possible influence of effects with similar optical signatures, such as plasmon resonances.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110339
Entities
People
- Matthew J. Berg
Organizations
- Air Force Office of Scientific Research
- Kansas State University
- United States Air Force