Abstract:
The invention relates to a spectrometer assembly (10) containing: a radiation source (11) with a continuous spectrum; a pre-monochromator (2) for generating a spectrum with relatively little linear dispersion, from which a spectral segment can be selected, whose spectral bandwidth is less than or equal to the bandwidth of the free spectral range of the order in the echelle spectrum, for which the mean wavelength of the selected spectral segment can be measured with a maximum blaze efficiency; an echelle spectrometer (4) comprising means for wavelength calibration; an entry slit (21) on the pre-monochromator (2) and an intermediate slit assembly (3) comprising an intermediate slit and a local resolution radiation receiver (5) on the exit plane of the spectrometer for detecting wavelength spectra. The assembly is characterised in that the width of the intermediate slit (3) is greater than the monochromatic image of the entry slit generated by the pre-monochromator at the location of the intermediate slit and that means are provided for calibrating the pre-monochromator, by means of which the radiation that is reproduced in the detector of the radiation source with a continuous spectrum can be calibrated to a reference position.
Abstract:
A spectrometer includes: a collimating element configured for collimating a beam of light into a first one of a cross-dispersing element and an echelle grating, the grating in optical communication with the cross-dispersing element; a focusing element for receiving the light from a second one of the cross-dispersing element and the echelle grating and focusing wavelengths of the light onto a spatial light modulator; the spatial light modulator configured for selectively directing the wavelengths onto a detector for detection. A method of use and the method of fabrication are provided.
Abstract:
An echelle spectrometer arrangement (10) with internal order separation contains an echelle grating (34) and a dispersing element (38) for order separation so that a two-dimensional spectrum having a plurality of separate orders (56) can be generated, an imaging optical system (18, 22, 28, 46), a flat-panel detector (16), and predispersion means (20) for predispersing the radiation into the direction of traverse dispersion of the dispersion element (38). The arrangement is characterized in that the predispersion means (20) comprise a predispersion element which is arranged along the optical path behind the inlet spacing (12) inside the spectrometer arrangement. The imaging optical system is designed in such a manner that the predispersed radiation can be imaged onto an additional image plane (24) which does not have any boundaries in the predispersion direction and which is arranged along the optical path between the predispersion element (20) and the echelle grating (34). Optical means (20, 68) in the area of the predispersed spectrum are arranged to influence the spatial and/or the spectral beam density distribution on the detector (16).
Abstract:
A method for the wavelength calibration of echelle spectra, in which the wavelengths are distributed across number of orders is characterised by the steps: recording of a line-rich reference spectrum with known wavelengths for a number of the lines, determination of the position of a number of peaks of the reference spectrum in the recorded spectrum, selection of at least two first lines of known order, position and wavelength, determination of a wavelength scale for the order in which the known lines lie, by means of a fit function gamma m (x), determination of a provisional wavelength scale gamma (x) for at least one neighbouring order m 1, by means of addition/subtraction of a wavelength difference gamma FSR which corresponds to a free spectral region, according to gamma m 1(x) = gamma m (x) gamma FSR with gamma FSR= gamma m(x)/m, determination of the wavelengths of lines in said neighbouring order m 1, by means of the provisional wavelength scale gamma 1(x), replacement of the provisional wavelength of at least two lines by the reference wavelength for said lines as obtained in step (a) and repeat of steps (d) to (g) for at least one further neighbouring order.
Abstract:
A method for the wavelength calibration of echelle spectra, in which the wavelengths are distributed across number of orders is characterised by the steps: recording of a line-rich reference spectrum with known wavelengths for a number of the lines, determination of the position of a number of peaks of the reference spectrum in the recorded spectrum, selection of at least two first lines of known order, position and wavelength, determination of a wavelength scale for the order in which the known lines lie, by means of a fit function gamma m (x), determination of a provisional wavelength scale gamma (x) for at least one neighbouring order m 1, by means of addition/subtraction of a wavelength difference gamma FSR which corresponds to a free spectral region, according to gamma m 1(x) = gamma m (x) gamma FSR with gamma FSR= gamma m(x)/m, determination of the wavelengths of lines in said neighbouring order m 1, by means of the provisional wavelength scale gamma 1(x), replacement of the provisional wavelength of at least two lines by the reference wavelength for said lines as obtained in step (a) and repeat of steps (d) to (g) for at least one further neighbouring order.