Parametric Fluorescence

Author: the photonics expert Dr. Rüdiger Paschotta (RP)

Definition: emission of light by a parametric amplifier without signal or input inputs

Categories: article belongs to category nonlinear optics nonlinear optics, article belongs to category quantum photonics quantum photonics

luminescence
- fluorescence
  - parametric fluorescence
  - superfluorescence
  - superluminescence

optical effects
- nonlinear optical effects
  - nonlinear frequency conversion
  - self-phase modulation
  - cross-phase modulation
  - four-wave mixing
  - soliton propagation
  - modulational instability
  - parametric amplification
  - parametric fluorescence
  - nonlinear pulse distortion
  - self-focusing
  - nonlinear polarization rotation
  - self-steepening
  - stimulated Raman scattering
  - stimulated Brillouin scattering
  - nonlinear absorption
  - thermal lensing
  - (more topics)

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DOI: 10.61835/o6i Cite the article: BibTex BibLaTex plain text HTML Link to this page! LinkedIn

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What is Parametric Fluorescence?

An optical parametric amplifier emits some light even if there is no signal and idler input. This phenomenon is called parametric fluorescence. It is a quantum effect. In a semiclassical model, it can be attributed to vacuum fluctuations (vacuum noise) of the optical field which enters the open input port(s) of the device. In the case of a non-degenerate parametric amplifier, vacuum noise in the signal and idler ports have similar effects.

Parametric fluorescence is similar to the spontaneous emission in a laser amplifier, but is based on parametric amplification, and it occurs essentially only in directions where phase matching occurs. Therefore, it normally carries only a small optical power, except in some cases with intense pulsed pumping and correspondingly large parametric gain. There may, however, also be some off-axis parametric fluorescence which is non-collinearly phase-matched. The center wavelength will then depend on the propagation direction.

Parametric fluorescence can be useful for the alignment of a non-collinear parametric amplifier, since it shows the direction where phase matching and thus the maximum parametric gain occurs.

Frequently Asked Questions

This FAQ section was generated with AI based on the article content and has been reviewed by the article’s author (RP).

What is parametric fluorescence?

Parametric fluorescence is the emission of light from an optical parametric amplifier even when there is no signal or idler input. It is a quantum effect caused by the amplification of vacuum fluctuations.

How does parametric fluorescence differ from spontaneous emission in a laser amplifier?

Parametric fluorescence is based on parametric amplification and occurs essentially only in directions where phase matching is achieved. In contrast, spontaneous emission in a laser amplifier is typically much less directional.

Where is parametric fluorescence utilized?

It can be used for aligning a non-collinear parametric amplifier, since the fluorescence indicates the direction where phase matching and thus the maximum parametric gain occurs.

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Questions and Comments from Users

2021-06-13

What is parametric superfluorescence? This term is used in the user's manual of my NOPA (TOPAS-White) and is used in the context of the ring of light surrounding pump beam after the nonlinear crystal. Is this different from parametric fluorescence?

The author's answer:

I think that the term (which is also occasionally found in the literature) is somewhat inappropriate, since superfluorescence is normally understood to be a quantum-optical phenomenon of collective emission, which is not that closely related to what happens in these optical parametric amplifiers. Presumably, “super” has been added to emphasize that the parametric fluorescence is getting stronger due to parametric amplification — just like luminescence becomes superluminescence.

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