Method For Wide Spectral Coverage Echelle Spectrograph Design And Clibration

Echelle spectrograph utilizes cross-dispersion to get two-dimension spectra onthe detector. Due to the characteristics of echelle grating, such as large dispersiveangle, high diffraction orders and wide wavelength range blazed, echellespectrograph obtains higher dispersion, higher resolution, wider spectral coverage,and higher energy efficiency than traditional grating spectrometers. Thus, echellespectrograph has received much more attention in astronomical observation,environmental monitoring, military dfense and chemical analysis. Goodperformance echelle spectrograph with both wide spectral coverage and highresolution is the target of instrumental developers. Although echelle spectrographhas so many merits, it brings lots of difficulties for design. Because of theconstraints of the detectors and prism dispersive property, it is hard to develop widespectral range echelle spectrograph with high resolution. Besides, how to reduce andcalibrate echelle spectra is also another factor to limit the application of echellespectrograph.Given these reasons, the parameters calculation, wide spectral coverage opticaldesign, echelle spectra reduction and precise adjustment are all analyzed andresearched in this thesis. First, an efficient algorithm based on the limits of boundary is described, andthe mathematic model is developed between the system requirements, structureparameters and two-dimension echelle spectra. Utilizing this model, the effectiveparameters can be calculated for echelle spectrograph quickly, which provide avaluable method for users.Second, based on the limitations of detectors, two configurations are providedto extend the eschelle-spectral coverage: double-prism echelle spectrograph anddivided spectral range echelle spectrograph. The details of design are discussed.Third, analyzing the optical characteristics of echelle spectrograph, the methodof deducing the aberration is described to ensure the resolution over the wholespectral range. The optical design results of these two structures are given.Forth, an echelle spectral model with the image plane rotated factor isestablished, which can reduce two-dimension spectra to one-dimension spectraprecisely. And the method of signal spots position acquirement is discussed toimprove the precision of wavelength calibration.Fifth, according to the sensitivity of the optical elements, an accurateadjustment means is discussed, which can ensure the design goals.Sixth, combined the divide spectral range echelle spectrograph and ICP,specimen were measured and analyzed. Experiments show that multiple elementscan be detected within a short time correctly, and the echelle spectrograph can meetthe requirements of ICP-AES.Seventh, the software is developed with the functions of parameters design,echelle spectra reduction, element analysis, and image processing, which providesconvenience for users.