MIR spectroscopy systems comprising hierarchical spectral dispersion that enables fine spectral resolution and high sensitivity spectroscopy are disclosed. Hierarchical spectral dispersion is derived by employing at least two diffractive lens arrays, located on either side of a test sample, each receiving input radiation having an input spectral range and distributing the input radiation into a plurality of output signals, each having a fraction of the spectral range of the input radiation. As a result, the signal multiplication factor of the two arrays is multiplied in a manner that mitigates the propagation of wavelength harmonics through the system. In some embodiments, an emitter array comprising a plurality of spectrally selective emitters provides the input MIR radiation to a spectroscopy system. In some embodiments, spectrally selective detectors are used to detect narrow spectral components in the radiation after they have passed through the test sample.
