Related Experiment Video
Updated: May 18, 2026

Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Weak interference in the high-signal regime
Juan P Torres1, Graciana Puentes, Nathaniel Hermosa
1ICFO-Institut de Ciencies Fotoniques, UPC, Mediterranean Technology Park, 08860 Castelldefels (Barcelona), Spain. juanp.torres@icfo.es
Abstract:
Weak amplification is a signal enhancement technique which is used to measure tiny changes that otherwise cannot be determined because of technical limitations. It is based on: a) the existence of a weak interaction which couples a property of a system (the system) with a separate degree of freedom (the pointer), and b) the measurement of an anomalously large mean value of the pointer state (weak mean value), after appropriate pre-and post-selection of the state of the system. Unfortunately, the weak amplification process is generally accompanied by severe losses of the detected signal, which limits its applicability. However, we will show here that since weak amplification is essentially the result of an interference phenomena, it should be possible to use the degree of interference (weak interference) to get relevant information about the physical system under study in a more general scenario, where the signal is not severely depleted (high-signal regime).
Related Concept Videos
Interference and Superposition of Waves
Interference occurs in mechanical waves, such as sound waves, waves on a string, and surface water waves. Mechanical waves correspond to the physical displacement of particles. Hence,...
Sound Waves: Interference
Interference and Diffraction
Interference: Path Lengths
Two special sources may be considered when they are in phase. This can be easily achieved by feeding the two sources from the same source. An example would be synchronizing the two speakers by feeding them with the same source, such as the sound waves produced by a tuning fork. This setup ensures that the two sources have the same frequency and are...
Inductively Coupled Plasma-Mass Spectrometry (ICP-MS): Interferences
Reconstruction of Signal using Interpolation

