Since the interaction of a laser beam or otherwise called laser radiation with
droplets in pendant position is a key process in the data reported in the book, the
current chapter is dedicated to the description of the main properties of a laser beam of
the kind used in presented experiments. Basically, laser emits electromagnetic radiation
with particular properties described briefly in this chapter, such as: coherence (spatial
and temporal), directivity coupled with mode structure, narrow (lower than 0.1 nm)
spectral width, time structure of the emission (pulsed or continuous wave-cw),
polarisation state (which is in most cases linear or closed to linear), Gaussian
distribution of intensity in beam cross section, high beam energy, power and
brightness.
Keywords: Astigmatic beam, Asymmetric beam, Axial mode, Beam FWHM,
Beam power, Beam TFW, Beam waist, Brightness, Coherence length, Coherence
time, Directivity, Fluence, Gaussian laser beam, Laser active medium, Mode
structure, Monochromaticity, Optical resonator, Polarised beam, Polarisation
state.
