Method of wavenumber linearity dispersion optical system and imaging spectrometer

A design method of a wavenumber linearity dispersion optical system, comprising steps of:

• S1:
• building an optical system including a grating, a prism and an objective lens that are sequentially arranged, the grating adjoining the prism, wherein collimated light is split through the grating and the prism into rays of different wavenumbers, and the rays of different wavenumbers enter the objective lens at different angles and image on an image plane;
• S2:
• defining a linearity evaluation coefficient RMS, which is the root-mean-square error of intervals between equal-difference wavenumbers in an operating band on the image plane;
• S3:
• assuming a length of the image plane Y as a constant value, assigning a minimum value to the linearity evaluation coefficient RMS through adjustment to the vertex angle of the prism α, when the linearity evaluation coefficient RMS is at minimum, the vertex angle of the prism is α1;
• S4:
• acquiring compensations for distortion and longitudinal chromatic aberration of the objective lens based on the interval between the equal-difference wavenumbers in the image plane when the vertex angle of the prism is α1;
• and
• S5:
• optimizing the objective lens based on the compensations for distortion and longitudinal chromatic aberration of the objective lens to obtain an optimized optical system.