Laser Spectroscopy

Laser Spectroscopy

Laser spectroscopy allows the chemical analysis of a material by use of laser light. Often this technique predominates traditional analytic methods, because measurements with light usually perform fast, non-contact and without the need of sample preparations. Analysis can be done "online, onsite and insitu".
Suitable method for each task
The choice of a spectroscopic methode depends on considerations about selectivity (ability to distinguish between different species) and sensitivity (how faint an input signal can be successfully recognized). Furthermore general application conditions like size, costs and complexity have to be taken into a acount.

Atomic Emission Spectroscopy (AES) Glowing of excited Atoms

To perform emission spectroscopy the medium to analyze is brought to an exited energetic state. After a short time the system relaxes by emitting electromagnetic radiation. Energy and thus wavelength of this radiation depends on the material. With spectral analyses the material can be identified.
Sequence
At sufficient strong excitation ionization of atoms and molecules occurs. During relaxation between unbound states (1) or between unbound und bound states (2) no line spectra will be emitted, however, on transition between bounded states (3) they will. The spectral analysis gives conclusions about the medium and its concentration in the sample. If a high energetic laser beam is applied to ionize the sample, one speaks of Laser Induced Plasma Spectroscopy or Laser Induced Breakdown Spectroscopy (LIBS).