Solitons in a crystal
By creating an optical soliton in a microresonator, EPFL scientists have found a new light source that could serve in geo-navigation, telecommunications, spectroscopy and the hunt for new Earth-like planets.
The optical resonators are crystals shaped to form a resonator that can guide a soliton light pulse on an endless circular path. When such a soliton light pulse circulates inside the resonator, a small fraction of it can be extracted every time the pulse completes one roundtrip.
The scientists at EPFL's Laboratory for Photonics and Quantum Measurement analyzed the extracted light pulses from the resonator and found them to be surprisingly short in duration; much shorter in fact than one millionth of one millionth of a second. Due to the small size of the optical resonator, the time between two extracted pulses is extremely short and the pulse rate very high.
Besides being of large scientific interest, the high rate of repeated ultra-short light pulses is important for many applications: In astronomy, it can be used to search for Earth-like planets, chemists can identify unknown substances, and the capacity of today's telecommunication networks can be boosted by orders of magnitude. Moreover, the solitons can be used for low-noise microwave generation or in future space-based optical clocks, significantly improving today's geo-navigation. Together with EPFL's Tech-Transfer Office, the scientists have applied for a patent and hope that their discovery will soon prove itself in one of its many applications.
Herr T, Brasch V, Jost JD, Wang CY, Kondratiev NM, Gorodetsky ML and T. J. Kippenberg. 2013 Temporal solitons in optical microresonators. Nature Photonics, 22 December 2013. DOI: 10.1038/NPHOTON.2013.343