Lasers, hell yeah

What’s he building in there?

the Fulcrum
Published: Oct 10

The problem

Science and art are sometimes seen as the incompatible arch-enemies of human endeavours. But art can inspire science, and science can animate art.

The researcher

Christopher Smeenk, PhD candidate at the University of Ottawa, researches ultra-fast laser pulses at the NRC-uOttawa Joint Attosecond Science Laboratory. He is also a musician who plays guitar and French horn. For Smeenk, there is no sharp separation between science and art, and no reason why they can’t be blended.

The project

Smeenk is fascinated with the idea of creating performances that can be appreciated by more than one sense. In his eyes, visualizations during musical acts are separate performances, layered over the music—the instrument that produces the sound is distinct from the system that creates the visualization. His ideal is an experience that merges sensations, so Smeenk invented an instrument that creates both sound and light simultaneously.

The key

Smeenk calls his instrument the Laser Musicbox. Extremely short infrared laser pulses blast through the air, tearing electrons off their atoms and creating plasma. This short-lived plasma is the cause of both the sound and the colour. The hot plasma rapidly expands into the cool air around it, generating a shock wave (this is actually how lightning makes thunder). Smeenk fires laser pulses in quick succession, creating a train of shock waves. The space between the waves sets the notes we hear.

But the plasma does a second thing: light can travel faster through the plasma than through the air. This shifts the visible light from infrared to a beautiful oily continuum of colours. The shorter the laser pulse, the more colours are produced.

The laser that the Laser Musicbox needs to function is permanently housed in a National Research Council (NRC) laboratory, but Smeenk points out that the first laser was the size of an entire room. He expects that as technology moves forward, the Laser Musicbox could become a mobile instrument, and looks forward to working with musicians and composers. Rock on, lasers, rock on.

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