Threshold behavior and tunability of a diffusive random laser.

Area of Science:

• Optics and Photonics
• Condensed Matter Physics

Background:

• Diffusive random lasers exhibit complex lasing dynamics.
• Characterizing the lasing threshold and intensity saturation is crucial for understanding random laser behavior.

Purpose of the Study:

• To demonstrate that peak wavelength shift (tunability) can visualize the dynamics of the lasing threshold and intensity saturation in diffusive random lasers.
• To investigate the relationship between spectral features and random laser threshold dynamics.

Main Methods:

• Experimental manipulation of ink concentration and pump energy to induce peak wavelength shifts.
• Observation and analysis of spectral features, specifically peak wavelength shifts (tunability).
• Comparison of experimental results with theoretical models like replica symmetry breaking and Lévy statistics.

Main Results:

• Peak wavelength shift (tunability) serves as a single spectral feature to visualize random laser dynamics.
• A progressive shift from blueshift to redshift was observed upon crossing the lasing threshold.
• A unique random laser threshold regime, rather than a discrete point, was identified.
• High agreement was found between the experimentally observed threshold regime and predictions from replica symmetry breaking and Lévy statistics.

Conclusions:

• Peak wavelength shift is a powerful tool for understanding diffusive random laser dynamics.
• The identified threshold regime provides new insights into the complex behavior of random lasers.
• The convergence of experimental and theoretical methods validates their effectiveness in characterizing random lasers.