A Non-Demolition Photon Counting Method by Four-Level Inverted Y-Type Atom

Abstract

ABSTRACT-The semi-classical model of atomfield interaction has been fully studied for some multilevel atoms, e.g. Vee, , Cascade  , Y, and inverted Y and so on. This issue is developed into the full-quantum electrodynamics formalism, where the probe and coupling electromagnetic fields are quantized. In this article, we investigate the full-quantum model of absorption and dispersion spectrum of trapped four-levels inverted Y type atoms, interacting with a probe beam of photons as well as two-mode trapped coupling photons. It is shown that the measurement of the maximum of absorption of the probe field and its detuning gives us simply the number of two-mode coupling photons, individually. An experimental setup for this non-demolition photon counting method is proposed and the numbers of coupling photons are obtained analytically.

A Mach-Zehnder Interferometry Method for the Measurement of Photonic State Squeezing in Quantum Cavities

“…The CW and CCW states in Eqs. (14) and (15) are recombined by the second beam splitter BS 2 , and outgoing states are obtained by applying the beam splitter operator on the incoming states:…”

“…Recently, squeezing and entangled states have found many applications in different fields [5][6][7][8], and many experimental setups have been presented to check the properties and applications of quantum entangled states [9][10][11]. Measurement and manipulation of quantum states, especially in quantum cavities, are a milestone for the development and improvement of atom-photon interaction methods [12][13][14], quantum teleportation [15], quantum cryptography [16], measuring the Wigner function of cavity field [17,18], detecting photons in a cavity by non-demolition method [4,19], quantum information and invention of quantum computers [20,21], etc. A winner of the Nobel Prize, Serge Haroche, has presented an interesting non-demolition method for measuring Wigner function in a quantum cavity [12].…”