High-resolution dispersive spectrometers have fundamentally been limited in optical throughput due to the entrance slit, or in the case of scanning monochrometers, the exit slit. With advancements in optical thin film coatings, highly efficient volume phase holographic gratings, and solid state detector technology, the optical efficiency of a spectrometer has the potential to be upwards of 80 to 95%. A slit on the other hand typically rejects 75 to 95% of the light in order to achieve high spectral resolution, bringing the total optical efficiency of a high-resolution dispersive spectrometer down to less than 5% in most cases.
To address this etendue problem, Tornado Spectral Systems has manufactured dispersive spectrometer platforms based fundamentally on a proprietary invention called a high-throughput virtual slit (HTVS™). A virtual slit is a device that is able to achieve the same high-resolution benefits of an actual slit aperture but maintains nearly 100% light throughput, eliminating the classic trade-off between throughput and resolution.