Table of Contents
ISRN Optics
Volume 2013 (2013), Article ID 271951, 9 pages
Research Article

A Method for the Measurement of Photons Number and Squeezing Parameter in a Quantum Cavity

Department of Physics, University of Zanjan, P.O. Box 45196-313, Zanjan, Iran

Received 20 September 2013; Accepted 7 November 2013

Academic Editors: Y. S. Kivshar, X. Shu, and Y. Tsuji

Copyright © 2013 Ghasem Naeimi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Measurement of photons number in a quantum cavity is very difficult and the photons number is changed after each measurement. Recently, many efforts have been done for the nondemolition measurement methods. Haroche et al. succeed in recognizing existence or nonexistence of one photon in a quantum cavity. In this paper, we employ their experimental setup for a quantum nondemolition measurement and pump a coherent state in their quantum cavity. In this case, we could detect more photons in the quantum cavity by a measurement of a displaced Wigner function. It is also shown that the measurement of more than one photon is possible by the Haroche method by measuring just one point of displaced Wigner function. Furthermore, if the cavity field is filled by a superposition of two number states, the average number of photons within the cavity would be measurable. We show that their setup is also suitable to apply for the measurement of the squeezing parameter for the squeezed state of photons number in the quantum cavity successfully.