A method of investigating a sample (1) having an absorption within an infrared spectral range of interest, comprises the steps of creating measuring light (2) with a light source device (10), wherein the measuring light (2) includes wavelengths covering the infrared spectral range, directing the measuring light (2) through the sample (1) to a detector device (20) with a plurality of detector units (21), each of which comprising an infrared sensitive sensor section (22) and an associated metamaterial resonator section (23) having a specific spectral resonance line (3), wherein the spectral resonance lines (3) of the resonator sections (23) have different frequencies within the infrared spectral range, wherein the measuring light (2) is transmitted through the sample (1) to the resonator sections (23) and subsequently sensed by the sensor sections (22), wherein an output of each of the sensor sections (22) depends on the absorption of the sample (1) at the frequency of the spectral resonance line (3) of the associated resonator section (23), and providing at least one absorption characteristic of the sample (1) on the basis of the output of the sensor sections (22), wherein the sample (1) is arranged for providing near field coupling of electronic states of the sample (1) and photonic resonator states of the resonator sections (23), wherein, for each of the resonator sections (23), a resonance line attenuation is created, which is determined by a complex refractive index of the sample (1) at the frequency of the spectral resonance line (3) of the resonator section (23), and the output of each of the sensor sections (22) is determined by the resonance line attenuation of the associated resonator section (23). Furthermore, a spectrometer apparatus (100) for investigating a sample (1) is described, which has an absorption within an infrared spectral range of interest.