The Influence of Filter Slit on the Imaging Performance of the Solar Grating Spectrometer Based on Adaptive Optics

Abstract

The solar grating spectrometer is an essential tool to study the thermodynamics properties of the solar atmosphere with different height distributions, but its imaging performance will be degraded by the wavefront aberration generalized by the atmospheric turbulence. On the other hand, the narrow slit of the grating spectrometer will filter the wavefront aberration to some extent. The influence of the filter slit on the wavefront aberration and the correction requirement of the adaptive optics are analyzed theoretically and experimentally. We demonstrate that the influence of filter slit on the different types and magnitudes of wavefront aberration is different, and the RMS value of the wavefront aberration less than 0.3λ is down to below almost 60% after the filter slit, and it can lower the correction range requirement of the adaptive optics. The numerical simulation and experiment results show that: after the adaptive optics correction, the influence of the wavefront aberration on the spectral resolution is neglected, and the energy utilization is considerably improved; both numerical simulation and experiment results are in good agreement.