Spectral range

The first requirement is a source of infrared radiation that emits all frequencies of the spectral range being studied. This polychromatic beam is analyzed by a monochromator, formerly a system of prisms, today diffraction gratings. The movement of the monochromator causes the spectrum from the source to scan across an exit slit onto the detector. This kind of spectrometer in which the range of wavelengths is swept as a function of time and monochromator movement is called the dispersive type. 

Instead of an absorbing dye layer between the mica. Levins et al [57] used thin metallic films and developed a method for FECO analysis using an extended spectral range. 

Modern commercial lasers can produce intense beams of monochromatic, coherent radiation. The whole of the UV/visible/IR spectral range is accessible by suitable choice of laser. In mass spectrometry, this light can be used to cause ablation, direct ionization, and indirect ionization (MALDI). Ablation (often together with a secondary ionization mode) and MALDI are particularly important for examining complex, intractable solids and large polar biomolecules, respectively. 

Materials Spectral range, nm Resolution, lines / mm Exposure required, lj/cm Diffraction efficiency, % Reusabihty ... 

The materials discussed yield lasers operating ia the infrared and near visible spectral ranges. Many appHcations of lasers, such as printing or high density memories, requite as short a wavelength as possible. The III—V system most suitable for short wavelength visible operation is the (Al Ga Q In ... 

Optical Properties. The optical transmission of vitreous siUca is influenced by impurities and the forming process. Ultrapure vitreous siUca has the abihty to transmit from the deep ultraviolet, through the visible, and into the near-infrared spectral range. 

Substance A has an absorption spectmm in one or more regions of the ultraviolet or visible spectral range. Irradiation of A at a wavelength corresponding to one of the absorption bands results in formation of substance B, which has a visible absorption spectmm different from A. Most commonly, substance A is uncolored or only slightly colored, whereas substance B is colored or appears darker than A. 

A solvent free, fast and environmentally friendly near infrared-based methodology was developed for the determination and quality control of 11 pesticides in commercially available formulations. This methodology was based on the direct measurement of the diffuse reflectance spectra of solid samples inside glass vials and a multivariate calibration model to determine the active principle concentration in agrochemicals. The proposed PLS model was made using 11 known commercial and 22 doped samples (11 under and 11 over dosed) for calibration and 22 different formulations as the validation set. For Buprofezin, Chlorsulfuron, Cyromazine, Daminozide, Diuron and Iprodione determination, the information in the spectral range between 1618 and 2630 nm of the reflectance spectra was employed. On the other hand, for Bensulfuron, Fenoxycarb, Metalaxyl, Procymidone and Tricyclazole determination, the first order derivative spectra in the range between 1618 and 2630 nm was used. In both cases, a linear remove correction was applied. Mean accuracy errors between 0.5 and 3.1% were obtained for the validation set. 

It is shown, that the offered approach allows to optimize a choice of a spectral range for cairying out of measurings and to recommend for a selected spectral range of value of the pai ameters of the equipment. It s permitting to implement measurings most efficiently. 

For characterization purposes of bulk or thin-film semiconductors the features at Eq and E] are the most useflil. In a number of technologically important semiconductors (e.g., Hgi j d Te, and In Gai j ) the value of. ) is so small that it is not in a convenient spectral range for Modulation Spectroscopy, due to the limitations of light sources and detectors. In such cases the peak at E can be used. The features at Eq and are not useflil since they occur too far into the near-ultraviolet and are too broad. 

In the infrared spectral range in general Fourier transform (FT) interferometers are used. In comparison with dispersive spectrometers FTIR enables higher optical throughput and the multiplex advantage at equivalent high spectral resolution. In... 

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