Happy third of Advent!
Time for the third candle on our scientific Advent wreath...
Christmas is approaching fast and we are already lighting our third candle on our scientific Advent wreath! Each Sunday, researchers from the DOLPHIN group, led by Andreas Döpp, light up a candle – a weakly ionized plasma – to showcase techniques normally applied to their high-power laser experiments at the Centre for Advanced Laser Applications (CALA).
This week, the researchers use a hyperspectral camera to identify specific elements within the flame and their location. The full spectrum captured by the camera allowed them to pinpoint the presence of sodium and potassium, which likely originate from trace amounts of these elements in the candle wax.
The results show that the emission is stronger in the outer regions of the flame, where the combustion is more complete. Therefore, more atoms are excited, and the intensity of the emission lines is higher. The inner part of the flame, where unburned vapor is present, is cooler and therefore emits less strongly.
Hyperspectral cameras are particularly useful for fields like agriculture and biomedical imaging, for example to diagnose plant diseases and detect skin conditions. Hyperspectral imaging techniques are also used in laser diagnostics. At the DOLPHIN group, researchers combine optics with data driven methods to develop new tools for hyperspectral imaging.
Next week, we will reveal the final candle and method on our scientific Advent wreath!
middle: example spectrum at on point in the image.
right: emission intensities of sodium and potassium in a candle flame.
Pictures: Advent candles: AI-generated / Nina Beier; Measurements: Matilde Nunes, Johannes Altmann and Marguerite Dion