What is beam modulation and why is it used in atomic absorption?

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Expert Solution

The beam may be carried over free space, or propagated through an optical waveguide. Depending on the parameter of a light beam which is manipulated, modulators may be categorized into amplitude modulators, phase modulators, polarization modulators etc. Often the easiest way to obtain modulation of intensity of a light beam, is to modulate the current driving the light source,

Beam modulation turns on and off the beam by chopping the signal. This allows any signal strength due to emission spectra within the flame to be eliminated

This is because even the best monochromators can not provide a bandwidth that is narrower than the atomic absorption line. If the bandwidth of the incident radiation is wider than the line width, measurement will fail as absorption will be only a tiny fraction of a large signal which is difficult to measure and will result in very low sensitivities. Therefore, line sourcesor modulation beam with bandwidths narrower than that of the absorption lines must be used .

queen_honey_blossom answered 1 year ago

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