Abstract: The high-resolution mid-infrared spectrometer (HIRMES) under development for SOFIA (Stratospheric Observatory for Infrared Astronomy) is an instrument operating in the 25-122 µm spectral range with a spectral resolution R= ? ? /? ~100,000 and has two absorber-coupled transition edge sensor (TES) bolometric detector focal planes. We have developed novel NbTiN low stress absorber coatings which have the required optical impedance across the HIRMES operating band. The low intrinsic stress of the…