Mechanism of sonoluminescence
![A setup similar to the following is required to create a bubble that can sonoluminesce.](/Images/godic/202502/09/Sonoluminescence_Setup2540.png")
![Multi-bubble sonoluminescence creates many oscillating and collapsing bubbles that will emit light. Typically the light emission is weaker than with single-bubble sonoluminescence. The bright blue dots, which are viewable when the image is viewed at high resolution are the sonoluminescencing bubbles.](/Images/godic/202502/09/MBSLred2540.JPG")
![Bubble oscillations correspond to pressure anti-nodes](/Images/godic/202502/09/Acoustic_pressure_vs_bubble_radius2540.png")
![Upon the collapse of a bubble experiencing cavitation, a hot spot is produced for a small amount of time. That hot spot contains a high temperature core that is surrounded by a cooler outer shell.](/Images/godic/202502/09/Hot_Spot_Diagram2540.png")
Sonoluminescence is a phenomenon that occurs when a small gas bubble is acoustically suspended and periodically driven in a liquid solution at ultrasonic frequencies, resulting in bubble collapse, cavitation, and light emission. The thermal energy that is released from the bubble collapse is so great that it can cause weak light emission. The mechanism of the light emission remains uncertain, but some of the current theories, which are categorized under either thermal or electrical processes, are Bremsstrahlung radiation, argon rectification hypothesis, and hot spot. People are beginning to lean more towards thermal processes as temperatures have consistently been proven with different methods of spectral analysis. In order to understand the light emission mechanism, it is important to know what is happening in the bubble's interior and at the bubble's surface.