A pulsed balanced homodyne detector has been developed for precise measurements of electric field quadratures of pulsed optical quantum states. A high level of common mode suppression (> 85 dB) and low electronic noise (730 electrons per pulse) provide a signal to noise ratio of 14 dB for the measurement of the quantum noise of individual pulses. Measurements at repetition rates up to 1 MHz are possible. As a test, quantum tomography of the coherent state is performed and the Wigner function and the density matrix are reconstructed with a 99.5% fidelity. The detection system can also be used for ultrasensitive balanced detection in cw mode, e.g. for weak absorption measurements.
@article{arxiv.quant-ph/0104084,
title = {An ultra-sensitive pulsed balanced homodyne detector: Application to time-domain quantum measurements},
author = {H. Hansen and T. Aichele and C. Hettich and P. Lodahl and A. I. Lvovsky and J. Mlynek and S. Schiller},
journal= {arXiv preprint arXiv:quant-ph/0104084},
year = {2009}
}