Nothing moves faster than the speed of light, but optical research is in hot pursuit. Once again, the Optical Society of America has recognized researchers at INRS for their groundbreaking advances, placing two INRS discoveries on the “Optics in 2018” year-end list published by Optics & Photonics News. According to the panel of guest editors assembled by the OSA, José Azaña’s and Jinyang Liang’s work ranks among the top 30 most exciting research discoveries internationally. They are the only researchers in Canada included in this year’s list.
INRS professors José Azaña and Jinyang Liang
Spectral invisibility cloak
team recently broke new ground by demonstrating that it is possible to conceal an object illuminated by broadband light without altering the profile of the illumination wave. His new approach to invisibility is called spectral invisibility cloaking.
A host of approaches to invisibility cloaking have emerged over the past decade. In order for an object to be completely concealed, the illumination wave and the target must not interact. The spectro-temporal wave profile cannot be modified by the target object or the cloaking device. A bona fide invisibility cloak must also be able to conceal objects under broadband illumination such as white light, which is composed of many frequencies (colours).
Until now, proposed solutions involved deflecting light around objects and were only effective for a single frequency. These approaches inevitably modified the spectro-temporal profile of broadband waves, revealing the presence of the invisibility cloak.
The concealment technique developed by Azaña’s team reversibly redistributes the spectrum of the illumination wave to frequencies that are not reflected by the object. The transformed waves propagate freely through the object without interacting with it. The initial wave profile is reestablished once the transformed waves have passed through, making the object invisible to observers, who only see the reconstructed wave.
INRS researchers demonstrated the concept with equipment commonly used in fibre optics. Spectral cloaking paves the way for the development of invisibility cloaks that work for physical objects in real-world conditions and has immediate potential applications in telecommunications, information processing, and other fields.
The world’s fastest camera
INRS professor Jinyang Liang
has developed T-CUP: the world’s fastest camera, which is capable of capturing 10 trillion (1013) frames per second. This new camera literally makes it possible to freeze time and see phenomena in extremely slow motion.
Using current imaging techniques, measurements taken with ultrashort laser pulses must be repeated many times, which is appropriate for some types of inert samples, but impossible for other more fragile ones. For example, a sample of living biological tissue can only tolerate a single laser pulse, leaving less than a picosecond to capture the results. By making real-time imaging 100 times faster, and setting a world record in the process, T-CUP can fuel a new generation of microscopes for biomedical, materials science, and other applications. In fundamental terms, this new camera makes it possible to analyze interactions between light and matter at an unparalleled temporal resolution.
The first time it was used, the ultrafast T-CUP broke new ground by capturing the temporal focusing of a single femtosecond laser pulse in real time. This process was recorded in 25 frames taken at an interval of 400 femtoseconds and detailed the light pulse’s shape, intensity, and angle of inclination.
Who will shine in 2019?
The annual OSA ranking showcasing advances in optical science has been been a year-end highlight for faculty at INRS’s Energy Materials Communications Research Centre for a number of years. Professor Robert Morandotti made the the list not once but twice in 2017 and was also featured in 2016. Professor José Azaña is no newcomer either; his work was given the nod in 2014, 2016, and 2017. And Professor Jinyang Liang was recognized by the OSA in 2015 during his tenure at Washington University in St. Louis, Missouri.
The bets are on: which discoveries will shine bright in 2019?