Systems and methods for measuring a fundamental mode vibrational spectrum of materials and substances in the Mid-IR spectral range of 2.5 μm to 14 μm wavelength. are disclosed herein. In one embodiment, a Mid-infrared absorption spectrometer (MIRAS) system includes an infrared Micro-Electro-Mechanical System (MEMS) single element emitter light source. The light source is electrically pulsed and emits electromagnetic radiation in the wavelength range from 2.5 μm to 14 μm and has an integral energy concentrating optic to provide energy for a spectral absorption process. The system includes a scanning high-efficiency infrared spectral grating with self-calibrating feature, configured so that incident energy having absorption information for the spectral absorption process of a sample is within a predefined threshold of a grating blaze angle. The system also includes a single-element thermal detector to receive output energy having the absorption information from the infrared spectral grating.