Design of stray light suppressed digital micromirror device-based spectrometer with compound parabolic concentrator

To suppress the stray light caused by the diffraction and scattered light of a digital micromirror device (DMD) in a DMD-based spectrometer, a new concentrator system with a compound parabolic concentrator (CPC) is presented, which has the advantage that all stray light beyond the acceptance angle can be rejected with the most compact device available. The diffraction of DMD is explored to determine the acceptance angle, and the parameters of the concentrator system are analyzed to determine the geometric concentration ratio. The simulation results show that the spectrum concentration efficiency of the CPC is 98.7%, that the stray light concentration efficiency from the DMD is 36.3%, and that the stray light concentration efficiency beyond the acceptance angle is 0.00%. Finally, according to the discussion about tolerance on the CPC, a conclusion can be drawn that the new DMD-based spectrometer with CPC is feasible and significant in suppressing the stray light.