Bistable enhanced total reflection in Kretschmann configuration containing a saturable gain medium

Area of Science:

• Optics and Photonics
• Condensed Matter Physics
• Nonlinear Optics

Background:

• Investigates light reflection from a Kretschmann configuration, a setup known for surface plasmon excitation.
• Utilizes a saturable gain medium, characterized by a classical Lorentzian oscillator model for its dielectric constant.
• Focuses on the phenomenon of enhanced total reflection (ETR).

Purpose of the Study:

• To theoretically investigate the optical bistability in a Kretschmann configuration with a saturable gain medium.
• To analyze the influence of gain saturation on enhanced total reflection (ETR) hysteresis loops.
• To examine the effects of incidence angle, metal film thickness, and small-signal gain on bistable ETR.

Main Methods:

• Theoretical modeling of TM-polarized light beam reflection.
• Excitation of surface plasmon polaritons in the Kretschmann configuration.
• Analysis of optical bistability and hysteresis loops arising from gain saturation.

Main Results:

• Demonstrates that effective excitation of surface plasmon polaritons leads to hysteresis loops in ETR curves.
• Shows that gain saturation is the cause of optical bistability.
• Details the impact of angle of incidence, metal film thickness, and small-signal gain on bistable ETR in homogeneously broadened (HB) media.

Conclusions:

• Gain saturation in the Kretschmann configuration with a saturable gain medium induces optical bistability.
• HB and inhomogeneously broadened (inHB) gain media exhibit analogous results but differ significantly in switching thresholds and hysteresis width.
• The study provides insights into controlling and understanding nonlinear optical phenomena in plasmonic systems.