Angular distribution of random laser emission

Area of Science:

• Optics and Photonics
• Condensed Matter Physics

Background:

• Random lasers (RLs) exhibit unique emission properties.
• Understanding the diffusive regime in RLs is crucial for their application.

Purpose of the Study:

• To experimentally analyze the angular distribution of emission from a random laser.
• To investigate the conditions leading to stable, angularly preserved spectral features in RLs.
• To identify a potential equivalent to the random laser critical volume.

Main Methods:

• Fabrication of a random laser using silica particles in a methanol:water matrix with Rhodamine 6G dye.
• Operation of the RL in the diffusive regime (approximately 1% scatterer volume fraction).
• Experimental analysis of the angular emission distribution and spectral features under varying pumping energy and scattering strength.

Main Results:

• Stable spectral features were observed under specific pumping-energy-dependent scattering strengths.
• These stable features were found to be angularly preserved.
• A novel parametric condition, potentially analogous to the RL critical volume, was identified.

Conclusions:

• The study identifies a new condition for stable, angularly preserved emission in diffusive random lasers.
• This finding may offer a new perspective on the critical volume concept in random laser theory.
• The results contribute to a deeper understanding of random laser physics and potential applications.