Optical Thermodynamics – Unlocking New Ways to Manipulate Light in Multimode Nonlinear Photonic Systems
dr inż. Paweł Jung, Warsaw University of Technology

Date, Time
10.07, 15:00 - 16:00

Location
hybrid meetnig (room 16), link (MSTeams) >>>

Photonics has revolutionized modern technology, powering critical applications in ultrafast telecommunications, high-precision sensing, and spectroscopy. Yet as the demand for advanced information processing—both classical and quantum—continues to rise, conventional light-based systems are approaching their performance limits. How can we push beyond these boundaries and achieve more effective light manipulation?

One promising approach involves multimode nonlinear waveguides and cavities, which offer increased information capacity by exploiting their expanded degrees of freedom. However, these complex systems pose significant challenges: high-power multimode sources can be vulnerable to cascading failures caused by imperfections, and nonlinear interactions among multiple modes often lead to chaotic dynamics and signal degradation.

Amid these challenges, fascinating behaviors emerge. A striking example is beam self-cleaning, where a multimode optical beam transitions from a disordered speckle pattern into a coherent Gaussian profile via nonlinear effects. Traditional tools from nonlinear dynamics frequently fall short in describing such phenomena. To address this, we propose a new theoretical framework—optical thermodynamics—which applies principles from thermodynamics and statistical mechanics to better understand and predict the behavior of multimode photonic systems.

In this talk, I will present our latest results using this emerging framework. I will highlight our experimental observation of optical thermodynamic processes at negative temperatures, which opens new possibilities for controlling light in complex, highly multimode nonlinear regimes. I will also outline future research directions, including the prediction of phase transitions between weakly and strongly nonlinear regimes in multimode photonic architectures.