Spectrometer and interferometric method
The invention relates to a spectrometer, a spectrometric method and detector, and a new use of an interferometer. The spectrometer comprises a Fabry-Perot interferometer ( 120 ), to which light can be guided from the object ( 100 ) being investigated, in order to produce an interference image, and a detector ( 130 ) at which the interference image is aimed. The transmittance of the interferometer ( 120 ) is spectrally sliced to at least two separate wavelength bands. For its parts, the detector ( 130 ) is arranged to detect the interference image from at least two separate wavelength bands spatially. The detector is arranged to detect the said wavelength bands simultaneously, by exploiting the response of the image elements of the detector, calibrated as a function of the mirror gap of the interferometer, in order to detect simultaneously at least two different orders of the interference. With the aid of the invention, it is possible to implement spectrometric measurements more quickly, or to obtain more information on the object at one time.
1. Spectrometer, which comprises
an interferometer, to which light is guided from an object being investigated, in order to produce an interference image, and
a detector to which the interference image is directed,
wherein
the interferometer is a Fabry-Perot interferometer, its transmittance is spectrally sliced to at least two separate wavelength bands, and its mirror gap is adjusted to select desired wavelength bands, and
the detector comprises a matrix of photosensitive image elements and is arranged to detect the interference image from at least two separate wavelength bands spatially, and
the detector is arranged to detect said at least two separate wavelength bands simultaneously, a response of -image elements of the detector being calibrated as a function of the mirror gap of the interferometer.
2. Spectrometer according to claim 1 , wherein the detector comprises a semiconductor matrix in each element of which there is an image element sensitive to each of the said at least two separate wavelength bands.
3. Spectrometer according to claim 1 , wherein the detector comprises means for optical separation of the said at least two separate wavelength bands, as well as means for detecting the optically separated beams locally.
4. Spectrometer according to claim 1 , wherein a radiation beam obtained from the object is guided through the interferometer in a collimated manner.
5. Spectrometer according to claim 1 , which further comprises at least one light source that produces a narrowband light signal in at least two of the said at least two separate wavelength bands.
6. Spectrometer according to claim 5 , wherein said light source is further arranged to produce light in bands that correspond to the wavelength bands of the detector in such a way that the maxima of the wavelength bands of said light source remain within a half-band width of corresponding bands of the detector.
7. Spectrometer according to claim 1 , wherein wavelength bands of the interferometer are arranged to correspond to wavelength bands of the detector in such a way that the maxima of the wavelength bands of the interferometer remain within a half-band width of the corresponding bands of the detector.
8. Spectrometer according to claim 1 , wherein at least part of the spectrometer is integrated in an optomechanical plastic structure.
9. Method for interferometrically investigating an object, comprising:
guiding light from the object to an interferometer in order to produce an interference image, and
aiming the interference image created further at a detector,
using as said interferometer a Fabry-Perot interferometer, which has a transmittance in a wavelength band of the light used for at least two separate spectrally sliced wavelength bands, and a mirror gap of which is adjusted, and
detecting at least two wavelength bands spatially on the detector with the aid of a matrix formed by photosensitive image elements,
detecting the said at least two separate wavelength bands on the detector by exploiting response of the image elements of the detector calibrated as a function of the mirror gap of the interferometer, for simultaneously detecting at least two different orders of interference.
10. Method according to claim 9 , wherein the object is illuminated with the aid of at least two light sources with a narrow wavelength band.
11. Method according to claim 9 , wherein the object is illuminated with at least one broadband light source.
12. Method according to claim 9 , the method further comprising providing, as at least part of said matrix, a CCD or CMOS cell comprising image elements sensitive to several wavelength bands.
13. Method according to claim 9 , the method further comprising optically separating wavelength bands before said detecting at least two wavelength bands.
14. Method according to claim 9 , comprising
using an optical element to collect light from the object,
guiding the collected light in a collimated manner through the interferometer, and
electrically detecting separately the responses produced by at least two wavelength bands passing through the interferometer.