Presented by: Oumin Shan, Polytechnic University of Milan and NIREOS
Dispersive spectrometers are compact, industrial-grade devices capable of measuring the spectrum of light from the visible to the infrared (IR) spectral regions. However, the presence of an entrance slit limits throughput and introduces a trade-off between sensitivity and spectral resolution. A different approach to measuring this spectrum of light is to use Fourier transform (FT) spectrometers, which record the interference signal produced by an interferometer. In these devices, the entrance slit is absent, thus providing higher throughput (the so-called Jacquinot advantage). However, FT spectrometers can be bulky and expensive, and they can suffer from environmental vibrations. For these reasons, they cannot easily be used in the ultraviolet-visible (UV-VIS) spectral regions, where a high degree of stability is required; therefore, they are restricted to the IR and to research labs.
In this presentation, Shan describes an ultrastable, common-path (CP) interferometer called GEMINI. The CP design automatically guarantees phase locking between the two interfering replicas. In this way, the device is compact and insensitive to external perturbations, and it can bring all the advantages of FT spectroscopy down to the UV-VIS spectral regions, displaying a flat spectral response from 250 to 3500 nm. The operation principle of the interferometer will be presented, together with a few applications such as in fluorescence detection and hyperspectral imaging.
About the presenter
Oumin Shan graduated with a bachelor's degree in physics engineering and a master's degree in photonics and nano-optics engineering from the Polytechnic University of Milan. After working at Accenture, an IT consulting company, he returned to the university for his doctorate, working on developing a novel device for spectroscopy. He is also an R&D engineer at NIREOS, a company that develops and manufactures optical and electronic devices for spectroscopy and hyperspectral imaging.