Laser fundamentals 1 Flashcards
What does the acronym ‘LASER’ stand for?
Light Amplification by Stimulated Emission of Radiation
What is the active medium in a laser?
The active medium is the material that amplifies light by controlled emission of photons.
What is the first lasing condition?
The first lasing condition is the requirement for population inversion, where more atoms are in the excited state than in the ground state.
What is the second fundamental component required to make a laser?
The second component is the feedback system provided by a carefully designed optical resonator.
What is a resonator mode?
A resonator mode is a specific optical mode that exists as a standing wave within a cavity, determined by the resonance condition ( \lambda_q = q\lambda = 2d ).
How are resonator modes quantized?
Resonator modes are quantized in energy, frequency, and wavevector, corresponding to specific energy levels along each axis.
What does the Boltzmann distribution describe in the context of lasers?
The Boltzmann distribution describes the probability of having a particle in the cavity with a specific energy, based on the temperature of the cavity.
What is the Bose-Einstein distribution?
The Bose-Einstein distribution describes the probability of finding a number of bosons, such as photons, in a cavity at a given energy level in thermal equilibrium.
What is the Fermi-Dirac distribution?
The Fermi-Dirac distribution describes the probability distribution for fermions, like electrons, in a quantum system where each state can contain either 0 or 1 particle.
What is blackbody radiation?
Blackbody radiation is the radiation emitted by an idealized object that absorbs all incident electromagnetic radiation and re-emits it according to its temperature.
What is Planck’s law?
Planck’s law describes the spectral energy density of blackbody radiation, accounting for the quantum nature of light.
What is spontaneous emission in laser physics?
Spontaneous emission is the process by which an excited atom emits a photon and returns to a lower energy state without any external influence.
What is stimulated emission?
Stimulated emission is the process where an incident photon stimulates an excited atom to emit an additional photon with the same phase, frequency, and direction.
What are Einstein coefficients?
Einstein coefficients (A and B) describe the probabilities of spontaneous emission (A) and absorption or stimulated emission (B) in atomic transitions.
How are the Einstein coefficients A and B related?
The Einstein coefficients are related by the equation ( B_{21} = B_{12} ), and ( A_{21}/B_{21} = 8\pi h
u^3/c^3 ), indicating a balance between spontaneous and stimulated processes.
