Can we cancel light waves?

Noise cancelling headphones filter out sound waves that we don’t want to hear. Listener Ahmed in Libya loves wearing his and, as he was listening to them, he had a thought: ‘Could we cancel out light waves in a similar way to how noise cancelling headphones do it?’ He sent his question to CrowdScience and now presenter Alex Lathbridge is getting deep into the physics, to find out if light cancelling devices could replace curtains and shutters. Alex starts at the Ray Dolby Centre in Cambridge in the UK, built to honour Ray Dolby’s invention of noise cancelling technology. In this amazing building he meets Jeremy Baumberg, Professor of Nanophotonics at Cambridge University. With the help of a tuning fork and a laser beams, Jeremy shows Alex that manipulating light is no easy feat. Undeterred, Alex tracks down Stefan Rotter, Professor of Theoretical Physics at Vienna Technical University in Austria. Stefan and his colleagues around the world have been pushing forward the development of a device called the ‘anti-laser’. Alex and Stefan explore whether this could be the light-cancelling device of Ahmed’s imagination. And once we've created a light-cancelling device, what do we do with it? Mary Lou Jepsen is an inventor and the founder of health tech firm Openwater. She tells Alex about how she’s using light wave manipulation to open up new possibilities for medical imaging, and even treatment. This programme includes clips from: Surrounded by Sound: Ray Dolby and the Art of Noise Reduction https://www.bbc.co.uk/programmes/m002bswq CrowdScience: Can we trap light in a box? https://www.bbc.co.uk/programmes/w3cswvwy Presenter: Alex Lathbridge Producer: Tom Bonnett Editor: Ben Motley (Photo: Eyesight and vision concept - stock photo Credit: J Studios / Getty Images)