Coherence_and_Interference Flashcards
What is an optical resonator?
An optical resonator is a device that confines and stores light at particular frequencies by guiding the propagation of light along a path that causes it to come back along itself.
What is coherence in the context of light?
Coherence refers to the ability of light to interfere. It is a measure of how well light waves are correlated in frequency, phase, and polarization.
Define temporal coherence.
Temporal coherence refers to the correlation of light waves at different times, which is quantified by the coherence function. It is related to the coherence time, a measure of how long the wave remains coherent.
What is the significance of the Wiener-Khinchin theorem?
The Wiener-Khinchin theorem states that the power spectral density of a signal is the Fourier transform of its autocorrelation function, linking coherence properties to the spectral width.
What is the coherence time of a light source?
Coherence time is the time duration over which a light wave maintains a certain level of coherence, indicating how predictable the wave’s phase and amplitude are over time.
How is coherence length defined?
Coherence length is the distance over which light waves remain coherent. It is the product of the coherence time and the speed of light.
Explain the role of interferometers in measuring coherence.
Interferometers split light into two paths, recombine them, and measure the resulting interference pattern. The pattern’s visibility is used to quantify the coherence of the light source.
Describe the function of a Michelson interferometer.
A Michelson interferometer splits a light beam into two paths, reflects them back using mirrors, and recombines them to create interference patterns, which are used to measure coherence and other optical properties.
What is a Fabry-Perot interferometer?
A Fabry-Perot interferometer consists of two parallel, partially reflective surfaces. Light bounces back and forth between the surfaces, creating multiple interfering beams, which are used to study spectral properties.
What does the Airy formula describe?
The Airy formula describes the transmitted and reflected amplitudes of light through a Fabry-Perot interferometer, taking into account the phase shifts and multiple reflections within the device.
