H. Hansen et al., Ultrasensitive pulsed, balanced homodyne detector: application to time-domain quantum measurements, OPTICS LETT, 26(21), 2001, pp. 1714-1716
A pulsed, balanced homodyne detector has been developed for precise measure
ment of the electric field quadratures of pulsed optical quantum states. A
high level of common mode suppression (> 85 dB) and low electronic noise (7
30 electrons per pulse) provide a signal-to-noise ratio of 14 dB for measur
ement of the quantum noise of individual pulses. Measurements at repetition
rates as high as 1 MHz are possible. As a test, quantum tomography of the
coherent state was performed, and the Wigner function and the density matri
x were reconstructed with 99.5% fidelity. The detection system can be used
for ultrarsensitive balanced detection in cw mode, e.g., for weak absorptio
n measurements. (C) 2001 Optical Society of America.