Long cavity spectral disperser at sub-picometer resolution. Design and analysis

In many applications of spectrometry, a very high spectral resolution is of paramount importance for technologies such as wavelength division multiplexing, femtosecond laser pulse shaping, chemical analysis of gases, or astrophysics observations. A few techniques achieving such goal already exist as listed in the introducing paragraphs. In this article is described a long cavity spectral disperser that is likely to be integrated into a spectrometer and having the potential to attaining unsurpassed spectral resolving power equal to ten millions or more. The basic relations of its angular dispersion, free spectral range, resolving power, transmission and contrast are established and a preliminary optimized design is presented