Double-grating polychromator for laser-aided plasma diagnostics

A wide bandpass double-grating polychromator with high rejection and high transmission has been designed and manufactured for laser-aided plasma diagnostics. The special mount utilizes subtractive dispersion in the second stage of the double polychromator such that the larger dispersion of the second stage is reduced by that of the first stage. This affects the intensity of the stray light background at the laser wavelength. The background at the edge of the laser line was measured at 10−5 of the light incident on the input slit. At the short end of the 200 nm bandpass, the stray light relative intensity approached 10−7.