The handedness of light holds the key to better optical control

Researchers at Aalto University鈥檚 School of Electrical Engineering have developed a new approach to control the properties of a light beam. By using the handedness of the light beam, the technique achieves significantly enhanced performance together with a more compact footprint.
鈥楬andedness or chirality is everywhere, from electrons to molecules, from our hands to spiral galaxies. Light also has handedness. Our modulation method uses the handedness of light by selecting certain polarizations via the crystal structure of the material in the device. It鈥檚 a fundamentally different approach from previous methods,鈥 says Yi Zhang, the postdoctoral researcher who led the study.
Optical modulators are used to manipulate the properties of a beam of light, such as its intensity, phase, or polarisation. Switching between states (for example, between adjustable and zero intensity) is a cornerstone of optical technologies, such as fibre optic communications, laser-based displays, and optical computing.
Current optical modulators mainly use electrical or acoustic effects to modulate light鈥檚 properties indirectly. 鈥楾hese two traditional optical modulator technologies can control the properties of light at nanosecond speeds . Our all-optical modulator, which uses a coherent optical process, can work at femtosecond speeds, or about a million times faster,鈥 Zhang notes.
Zhang believes the technology will be easy to transfer from lab to application, where it offers possible improvements in a wide range of fields, from fibre optics to display technologies. 鈥楾he principle we used to modulate the light more quickly and efficiently is quite clear, and I believe it could be applied very soon,鈥 Zhang says.
Professor Zhipei Sun, the group leader, says that 鈥榯his new method holds great promise for advanced nonlinear optical devices, computing, and quantum technologies. It also provides extra choices of materials for current devices, which is beneficial for companies that produce optical modulators.鈥
The study was published in the journal .
Read more news

Time crystals could power future quantum computers
A time crystal, a long-life quantum system approaching perpetual motion, has been hooked up to its environment for the first time, unlocking an intriguing way to increase quantum computational and sensing power.
Nanoparticles in Functional Textiles
Dr. Md. Reazuddin Repon, Postdoctoral Researcher at the Textile Chemistry Group, Department of Bioproducts and Biosystems, Aalto University, has contributed as an editor to a newly published academic volume titled 鈥淣anoparticles Integrated Functional Textiles鈥.
Introducing Qi Chen: Trustworthy AI requires algorithms that can handle unexpected situations
AI developers must focus on safer and fairer AI methods, as the trust and equality of societies are at stake, says new ELLIS Institute Finland principal investigator Qi Chen