SPECTROSCOPY & LIBS

LITRON LASERS FOR SPECTROSCOPY & LIBS

Spectroscopy is an analytical technique used to gather information on the atomic and molecular level of virtually any substance via its interaction with electromagnetic radiation, either through the emission or absorption of a particular and characteristic set of wavelengths.

Spectroscopy long predates the advent of the laser but now lasers are used in virtually every aspect of it. Their narrow linewidth enables precise wavelength resolution to be achieved while the high peak powers from mode locked and Q-switched lasers enable nonlinear optical phenomena to be investigated.

Tunable sources, such as dye lasers, Ti:Sapphire lasers and OPO’s are particularly useful for generating complete absorption spectra or for accessing particular absorption lines to enable emission spectra to be gathered.

Pulsed Nd:YAG lasers are used for sample generation in LIBS and mass spectroscopy applications. Their high peak power and low beam divergence enable a plasma to be readily generated from any medium (gas, liquid or solid) under investigation.

In LIBS (laser induced breakdown spectroscopy), the plasma sample emits a characteristic set of wavelengths dependent on the elemental species present and thus the presence of particular elements may be determined with varying degrees of quantitative precision. Litron Lasers developed Bernoulli LIBS – a 1064nm low divergence compact laser, suitable for double pulsed LIBS. The Bernoulli LIBS contains two laser oscillators that are combined on to a single beam axis in a single head. The lasers are fitted with low divergence optics to ensure high focusability and make it highly suited to LIBS applications that utilise the double pulse technique. The pulses can be used to reheat the plasma or as cleaning pulses.

In mass spectroscopy, typically larger, charged fragments are generated (amongst other ways) by a laser and then the charge to mass ratio determined by accelerating them electrically through a known magnetic field.