Femtosecond Circular Photon Drag Effect in the Ag/Pd Nanocomposite

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Photoresponse in nanocomposite films is crucial for optoelectronic applications.
• Understanding light-matter interactions in metallic nanostructures is an active research area.

Purpose of the Study:

• To investigate the helicity-dependent photoresponse of silver-palladium (Ag/Pd) nanocomposite films.
• To elucidate the underlying physical mechanism responsible for the observed photoresponse.

Main Methods:

• Fabrication of 20-μm-thick Ag/Pd nanocomposite films.
• Irradiation with 120 fs pulses from a Ti:S laser.
• Measurement of the induced electric current perpendicular to the incidence plane.
• Analysis of current dependence on incident beam power, polarization (p-, s-, right- and left-circularly polarized), and angle of incidence.
• Comparison of experimental data with theoretical models.

Main Results:

• An electric current was induced in the Ag/Pd nanocomposite films.
• The photoinduced current exhibited a linear dependence on incident beam power.
• The sign of the current was dependent on the beam polarization and angle of incidence, being zero for p- and s-polarized beams and opposite for right- and left-circularly polarized beams.

Conclusions:

• The observed helicity-dependent photoresponse in Ag/Pd nanocomposite films is attributed to the photon drag effect.
• This finding provides insights into the fundamental light-matter interactions in metallic nanocomposites.