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radiative recombination

this energy is emitted in the form of a photon

non-radiative recombination

it is passed on to one or more phonons and in the case of Auger recombination it is given off in the form of kinetic energy to another electron

Band-to-band recombination

electron moves from its conduction band state into the empty valence band state associated with the hole

Trap-assisted recombination

occurs when an electron falls into a "trap"

Auger recombination

a process in which an electron and a hole recombine in a band-to band transition

population inversion

When the number of particles in the excited state is greater than the number of particlesin the ground state the material is in a state of

LED

The low energy part of the spectral

characteristics will be related to transitions between dopant levels and edge bands. The maximum of LED’s output power refers to the photon’s energy which is a little smaller

characteristics will be related to transitions between dopant levels and edge bands. The maximum of LED's output power refers to the photon's energy which is a little smaller

than the width of the energy gap. The phenomenon of "fill-band" is

than the width of the energy gap. The phenomenon of "fill-band" is

responsible for the high energy part of the spectral characteristics

and it is caused by the

increasing of the current flowing through the diode.

increasing of the current flowing through the diode.

The optical cavity

contains a coherent beam of light

between reflective surfaces-mirrors so that the light passes through the gain medium more

between reflective surfaces-mirrors so that the light passes through the gain medium more

than once before it is emitted from the output aperture or lost to diffraction or absorption

than once before it is emitted from the output aperture or lost to diffraction or absorption

resonator

in each passage through the active material the intensity gains

amplitude condition

reached when the optical gain of the laser medium is exactly

balanced by the sum of all the losses experienced by light in one round trip of the laser's

balanced by the sum of all the losses experienced by light in one round trip of the laser's

optical cavity.

optical cavity.

phase condition

obtained when the phase of the signal in cavity is equal the phase

of the signal after transition through whole resonator

of the signal after transition through whole resonator

The threshold current

current at which optical gain of the laser medium equals the

sum of all the losses

sum of all the losses