Reduction in generalized conductance with increasing gain in amplifying Anderson-localized systems

Area of Science:

• Photonics and Condensed Matter Physics
• Quantum Optics and Disordered Systems

Background:

• Anderson localization describes wave function confinement in disordered systems.
• Nonconservative environments, featuring gain or loss, significantly alter wave transport phenomena.
• Understanding photon transport in localized regimes with gain is crucial for optical device applications.

Purpose of the Study:

• To experimentally investigate the impact of gain on Anderson localization of photons.
• To quantify the changes in system conductance and localization length with added gain.
• To theoretically model the observed phenomena and explore emulation of high-disorder effects.

Main Methods:

• Experimental realization of a quasi-one-dimensional disordered system with tunable gain.
• Measurement of generalized conductance via variance of localized eigenfunctions.
• Theoretical modeling using transfer matrix calculations and rate equations for a two-level lasing system.

Main Results:

• A systematic decrease in photon localization length was observed upon addition of gain.
• Generalized conductance of the system showed a significant decrease with increasing gain.
• Theoretical models showed good qualitative agreement with experimental findings.
• Gain was shown to emulate higher disorder effects in weakly disordered systems.

Conclusions:

• Gain in a nonconservative environment reduces photon localization length and system conductance.
• The observed decrease in conductance is attributed to reduced photon outcoupling probability.
• This study provides insights into controlling light transport in disordered photonic systems.