Fundamentals

Properties of light

• Wavelength and frequency                                                                                                     Light is an electromagnetic phenomenon, and therefore a wave that travel at constant speed trough space a certain speed, which is given by the product of two quantities characterizing the entire wave: vibration frequency (nu) and wavelength (lambda). So nu x lambda = c = 3x10 ^ 8 m / s.

• Polarization                                                                                                                            When a flow of electrons (electric current) moves in a circular path (eg a coil of copper wire) arises pontaneously a magnetic force which is perpendicular to the turns of the coil. This force is observed by introducing a magnet inside the coil, which will be expelled or drawn in according to  the orientation of the magnet and the direction of current flow in the coil. Thus an electric current produces a magnetic field and both are perpendicular. Similarly a magnetic field may induce an electric current. This physical phenomenon is described by Maxwell's laws.                  We can then noted that an electromagnetic wave, a photon, is composed of an electrical and a magnetic component. The electrical component comes from an electric field and the magnetic component from a magnetic field, both are perpendicular to each other and mutually coexist. The amplitude of these fields change cyclically in time, depending on the frequency of the wave, but may also change depending on the position in space. Changes in the amplitude in space can take place randomly, linear, elliptical or circular. The change defines the polarization of light. The reflection and absorption of a photon by a solid medium are strongly influenced by the type of polarization.

• Energy and momentum                                                                                                         Each light wave corresponds to a bundle of energy called light quantum or photon, the photon energy is measured by E = h x nu, where h is Planck constant and nu is the frequency of vibration of the photon in Hertz, frequency that determines the color of the photon or light.           Similarly the momentum of the light quantum is given by Planck's constant divided by the wavelength in meters: p = h / lambda in newton x second                                                               The Planck constant value is h = 6.662 x 10 ^ -34 joule x second

Working principle of the laser

• Radiation absorption
• Spontaneous emission
• Stimulated emission
• Energy punping
• Amplification

Types of laser

• CO2 laser
• Nd:YAG laser
• Diode láser 
• Fiber laser

Severing processes

• Laser cutting

Joining processes

• Laser welding

Additive processes

• Laser sintering
• Laser deposition
• Laser alloying
• Laser cladding