The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Probing of delicate systems demands high sensitivity from limited probe energy. Quantum optical techniques to beat the standard quantum limit (SQL) offer a practical advantage for these measurements. Here we report the first entanglement-enhanced measurement of a delicate material system [1]. We non-destructively probe an atomic spin ensemble by near-resonant Faraday rotation, a measurement that is...
Probing of delicate systems demands high sensitivity from limited probe energy. Quantum optical techniques to beat the standard quantum limit (SQL) offer a practical advantage for these measurements. Here we report the first entanglement-enhanced measurement of a delicate material system [1]. We non-destructively probe an atomic spin ensemble by near-resonant Faraday rotation, a measurement that is...
NOON states are a class of path-entangled or polarization-entangled states consisting of N photons that achieves better performance in phase estimation compared to coherent states as input. These NOON states have proven to achieve super-resolution and to break the shot-noise limit. Ideally they achieve the Heisenberg limit for any value of the phase. This is an advantage over squeezed states, which...
The ability to measure magnetic fields with high sensitivity is a key requirement in many physical, biological and medical applications. Currently the most sensitive magnetometers are optical magnetometers, in which the polarization of an atomic sample responds to the field and is read out by an optical measurement. These instruments are limited by two fundamental sources of quantum noise: projection...
We demonstrate a light-shot-noise-limited magnetometer based on the Faraday effect in a hot unpolarized ensemble of rubidium atoms. By using off-resonant, polarization-squeezed probe light, we improve the sensitivity of the magnetometer by 3.2 dB.
There has been increasing interest in the generation of such photon pairs using a spontaneous parametric down-conversion (SPDC) source inside an optical cavity to enhance the down-conversion into modes resonant to the cavity, each of the modes having a MHz spectrum. These optical parametric oscillators (OPO) operated far below threshold also provide a well defined spatial mode. Our setup consists...
Atom-photon interaction promises to be a fundamental resource for applications like quantum computations. For an efficient interaction between light and atoms, the bandwidth of the light should match the natural linewidth of the atom transition to address, 6 MHz in the case of the Di line of rubidium. Cavity-enhanced down-conversion (CEDC) produces bright narrow-band quantum light with suitable linewidth...
We use narrow-band quantum light sources, tuned to the rubidium D1 resonance, to produce polarization-squeezed and polarization-NooN states for Heisenberg-limited measurements on atoms. By paramagnetic Faraday rotation these states measure the atomic spin polarization.
We describe an ultra-bright source of narrow-band pairs of indistinguishable photons based on cavity-enhanced down-conversion. This source is suitable for experiments on light-matter interactions at the single-photon level.
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.