Abstract
An important feature of a heterodyne laser Doppler vibrometer (LDV) is
the possibility of measuring an optical path length oscillation at a
frequency f at a choosable frequency
fhet ± f, at which the photo-electric measurement shows an optical
quantum noise that is significantly greater than the detector dark
noise. The full-squeezed light enhancement of a heterodyne LDV’s
signal-to-noise ratio has not been achieved so far. Here we use a
sideband spectrum that is squeezed around fhet = 40 MHz and demonstrate the
squeezing-enhanced measurement of an optical path length vibration at
f = 1 MHz of about 3.5 dB while fully
maintaining the signal power. The proof of principle we provide will
enable the realization of ultra-precise LDVs over an extended signal
bandwidth for probes or environments that require low intensities.
Funder
Deutsche
Forschungsgemeinschaft
Subject
Atomic and Molecular Physics, and Optics