In the 3.5 to 5µm range (mid-infrared), the instrument is capable of analysing the wavelength spectrum of lasers with a wavelength resolution of 0.2nm and a wavelength accuracy of ±0.5nm, increasing a laser’s capability to distinguish between various gases such as CO2, N2O and NO. Other key features of the AQ6377 include a high dynamic range of 50 dB, and a level sensitivity down to -60 dBm. The wide dynamic range and high sensitivity have been achieved by reducing the influence of stray-light in the monochromator. The built-in calibration light source takes advantage of the natural absorption properties of acetylene gas to deliver a wavelength calibration signal which is accurate to 0.6 picometres.
This source is also used in conjunction with the automatic optical alignment capability to compensate for any deviation in the optical axis caused by vibrations and shock suffered in transit, and those due to temperature changes. Using those features, the AQ6377 can maintain its high optical performance on site. In addition, the free-space optical input makes it possible to connect both single-mode MWIR fibres and multimode (up to 400 µm) to the same instrument, and delivers a low and stable insertion loss, which increases measurement repeatability. The lack of physical contact also eliminates the possibility of damage when fibres are connected. In the MWIR region, spectral measurements can be strongly influenced by the absorption of water vapour and carbon dioxide. A purging feature significantly reduces the influence of these gases by continuously supplying a pure purge gas, such as nitrogen, to the monochromator through the dedicated connectors on the back panel.
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