A Design Cycle for Echelle Spectrometers

Echelle spectroscopy is a mature technique that was introduced over 60 years ago. However, the process of determining all of the physical parameters of an echelle spectrometer, especially the main parameters of the echelle grating itself (the groove density, the blaze angle, and the grating’s size), is not easily found in the literature. This paper takes a systematic approach to the problem of designing an echelle spectrometer and develops a design cycle that starts with the main requirements of an echelle spectrometer: the wavelength range, the spectral resolution, and the geometrical optical throughput. It sorts all of the equations that relate the requirements to the physical parameters of the spectrometer, identifies the design parameters (those that are directly selected by the designer), and develops a tool that determines all of the physical parameters of an echelle spectrometer for any given set of requirements.