AAWSAP DIRD, Quantum Tomography of Negative Energy States in the Vacuum, January 2011

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UNCLASSIFIED//FOR OFFICl"L U.!I! er•tY
signal
a
detector
vacuum
I vacuum
"V~
I b1
detector
local
oscillator
(aw)
Figure 11. Balanced Homodyne Detector Using Fictitious
Beam Splitters to Account for Detection Losses. (courtesy
of Ulf Leonhardt)
Equation (12) provides an additional model for detection losses. Similar to direct
photon counting, a fictitious vacuum field has to be added to the attenuated signal in
homodyne detection. This means that we can replace the arrangement of two fictitious
beam splitters in front of the photodetectors with just one effective beam splitter in
front of an ideal homodyne detector (see Figure 12). This effective beam splitter
accounts for other kinds of losses including mode mismatch, whereby the quantum
effects of both detection losses and mode mismatch are comprised in an effective TJ.
UNCLASSIFIED//FOA OFFI@IAL li!II! er•t I
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