Spectral imaging of a sample using a plurality of discrete mid-infrared wavelengths

摘要

Spectrally analyzing an unknown sample (10A) includes (i) providing a spatially homogeneous region (10B) of the unknown sample (10A); (ii) directing a plurality of interrogation beams (16) at the spatially homogeneous region (10B) with a laser source (14), (iii) acquiring a separate output image (245) while the unknown sample (10A) is illuminated by each of the interrogation beams (16) with an image sensor (26A); and (iv) analyzing less than fifty output images (245) to analyze whether a characteristic is present in the unknown sample (10A) with a control system (28) that includes a processor. Each of the interrogation beams (16) is nominally monochromatic and has a different interrogation wavelength that is in the mid-infrared spectral range.

主权项

1. A method for spectrally analyzing an unknown sample for the existence of a characteristic, the method comprising:
analyzing a known sample having the characteristic to identify a plurality of diagnostic spectral features, each diagnostic spectral feature being present at a different diagnostic wavelength that is in a mid-infrared spectral region; providing a spatially homogeneous region of the unknown sample; directing a plurality of interrogation beams at the spatially homogeneous region with a laser source, each of the interrogation beams being nominally monochromatic and having a different interrogation wavelength; wherein each interrogation wavelength corresponds to a different one of the diagnostic wavelengths; acquiring a plurality of separate output images of the unknown sample with an image sensor that senses light in the mid-infrared spectral region, wherein each of the output images is acquired while the unknown sample is illuminated by a different one of the interrogation beams; and analyzing less than fifty output images to analyze whether the characteristic is present in the unknown sample with a control system that includes a processor; wherein the spatially homogeneous region of the unknown sample is substantially structurally homogeneous so that the interrogation wavelengths of the spectral features have shifted less than 10 cm−1 than expected when directed at the spatially homogeneous region.