Abstract:
A sensing apparatus consisting of more than one diode laser having select lasing frequencies, a multiplexer optically coupled to the outputs of the diode lasers with the multiplexer being further optically coupled to a pitch side optical fiber. Multiplexed laser light is transmitted through the pitch side optical fiber to a pitch optic operatively associated with a process chamber which may be a combustion chamber or the boiler of a coal or gas fired power plant. The pitch optic is oriented to project multiplexed laser output through the process chamber. Also operatively oriented with the process chamber is a catch optic in optical communication with the pitch optic to receive the multiplexed laser output projected through the process chamber. The catch optic is optically coupled to an optical fiber which transmits the multiplexed laser output to a demultiplexer. The demultiplexer demultiplexes the laser light and optically couples the select lasing frequencies of light to a detector with the detector being sensitive to one of the select lasing frequencies.
Abstract:
The invention relates to a spectrometer arrangement (10) comprising a spectrometer (14) for producing a spectrum of a first wavelength range of radiation from a radiation source on a detector (42). Said arrangement also comprises: an Echelle grating (36) for the spectral decomposition of the radiation penetrating the spectrometer arrangement (10) in a main dispersion direction (46); a dispersing element (34) for separating the degrees by means of spectral decomposition of the radiation in a transversal dispersion direction (48) which forms an angle with the main dispersion direction of the Echelle grating (36), in such a way that a two-dimensional spectrum (50) can be produced with a plurality of separated degrees (52); an imaging optical element (24, 38) for imaging the radiation penetrating through an inlet gap (20) into the spectrometer arrangement (10), in an image plane (40); and a surface detector (42) comprising a two-dimensional arrangement of a plurality of detector elements in the image plane (40). The inventive arrangement is characterised in that another spectrometer (12) comprising at least one other dispersing element (64) and another imaging optical element (60, 66) is provided in order to produce a spectrum (68) of a second wavelength range of radiation, which is different from the first wavelength range, from a radiation source on the same detector (42). The spectra can be spatially or temporally separated on the detector.