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Volume 4, Issue 4 (Suppl) J Laser Opt Photonics, an open access journal
ISSN: 2469-410X Optics 2017
November 15-17, 2017
November 15-17, 2017 | Las Vegas, USA
8th International Conference and Exhibition on
Lasers, Optics & Photonics
Parity detection achieving Heisenberg limit in an SU(1,1) interferometer with coherent and squeezed
vacuum input states
Dong Li
Microsystem and Terahertz Research Center, China
One common tool for precision measurement is interferometer. Compared with the conventional SU(2) interferometer, the
SU(1,1) interferometer utilizes parametric amplifiers for wave splitting and recombination. Due to parametric amplification
process, SU(1,1) interferometers have a better phase sensitivity than SU(2) ones under the same condition of input states. With
squeezed vacuum input, the phase measurement sensitivity of SU(1,1) interferometers can be improved. This improvement is due
to noise reduction. Here, we theoretically study parity detection on an SU(1,1) interferometer with coherent mixed with squeezed
vacuum input states. Parity detection counts the evenness or oddness of the photon number in one output mode. Our work shows
that parity detection reaches below Heisenberg limit when the input coherent and squeezed vacuum light are mixed in roughly equal
proportions with a strong parametric amplifier strength. Compared with homodyne detection, parity detection has a slightly better
phase sensitivity with coherent and squeezed vacuum inputs and parity detection is more suitable than homodyne detection in
some certain situations. Lastly, we also investigate the Quantum Cramer-Rao bound for SU(1,1) interferometers, showing that phase
measurement sensitivity does not surpass Quantum Cramer-Rao bound even though it surpasses Heisenberg limit. Parity detection
was initially proposed to applied with input N00N states and Fock states in SU(2) interferometers. Now, parity detection invades
SU(1,1) interferometers.
Biography
Dong Li has completed his PhD from East China Normal University. He is the Assistant Researcher of Microsystem and Terahertz Research Center. His research interests
include quantum metrology and quantum interferometry.
Dong Li, J Laser Opt Photonics 2017, 4:4 (Suppl)
DOI: 10.4172/2469-410X-C1-017