Coherent spectroscopy
Encyclopedia
Spectroscopy
is the study of light through light-matter interactions.
There are three main types of interactions:
- Quantized interactions in which involved molecule
s (Here: atoms, full or parts of molecules or crystals,..) jump from a stationary state
to another stationary state. It is the most usual spectroscopy.
- Coherent
interactions in which the involved molecules are excited to a non-stationary state during the interaction and return to their initial state.
A detectable effect requires the coherence, that is the relations between the molecular parameters allowing the interaction (oscillating dipoles...) and the local electromagnetic fields are the same for all molecules.
- Mixed interactions: coherent and involving transitions of some molecules; example : He-Ne laser
s.
Except refraction
which is widely used, the coherent interactions are generally studied using lasers, so that, due to the intensity of these sources, the effects depend non-linearly on the intensity of the lasers. Some interactions require an intensity threshold.
Spectroscopy
Spectroscopy is the study of the interaction between matter and radiated energy. Historically, spectroscopy originated through the study of visible light dispersed according to its wavelength, e.g., by a prism. Later the concept was expanded greatly to comprise any interaction with radiative...
is the study of light through light-matter interactions.
There are three main types of interactions:
- Quantized interactions in which involved molecule
Molecule
A molecule is an electrically neutral group of at least two atoms held together by covalent chemical bonds. Molecules are distinguished from ions by their electrical charge...
s (Here: atoms, full or parts of molecules or crystals,..) jump from a stationary state
Stationary state
In quantum mechanics, a stationary state is an eigenvector of the Hamiltonian, implying the probability density associated with the wavefunction is independent of time . This corresponds to a quantum state with a single definite energy...
to another stationary state. It is the most usual spectroscopy.
- Coherent
Coherence (physics)
In physics, coherence is a property of waves that enables stationary interference. More generally, coherence describes all properties of the correlation between physical quantities of a wave....
interactions in which the involved molecules are excited to a non-stationary state during the interaction and return to their initial state.
A detectable effect requires the coherence, that is the relations between the molecular parameters allowing the interaction (oscillating dipoles...) and the local electromagnetic fields are the same for all molecules.
- Mixed interactions: coherent and involving transitions of some molecules; example : He-Ne laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...
s.
Except refraction
Refraction
Refraction is the change in direction of a wave due to a change in its speed. It is essentially a surface phenomenon . The phenomenon is mainly in governance to the law of conservation of energy. The proper explanation would be that due to change of medium, the phase velocity of the wave is changed...
which is widely used, the coherent interactions are generally studied using lasers, so that, due to the intensity of these sources, the effects depend non-linearly on the intensity of the lasers. Some interactions require an intensity threshold.
See also
- Coherent anti-Stokes Raman spectroscopyCoherent anti-Stokes Raman spectroscopyCoherent anti-Stokes Raman spectroscopy, also called Coherent anti-Stokes Raman scattering spectroscopy , is a form of spectroscopy used primarily in chemistry, physics and related fields. It is sensitive to the same vibrational signatures of molecules as seen in Raman spectroscopy, typically the...
- Coherent Stokes Raman spectroscopyCoherent Stokes Raman spectroscopyCoherent Stokes Raman spectroscopy is a form of spectroscopy used primarily in chemistry, physics and related fields. It is closely related to Raman spectroscopy and lasing processes...
- Raman spectroscopyRaman spectroscopyRaman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range...