We experimentally generate a spatially squeezed light beam and realize a small-displacement measurement beyond the quantum noise limit with this squeezed light. Moreover, we measure about -2.2±0.2dB spatial squee...We experimentally generate a spatially squeezed light beam and realize a small-displacement measurement beyond the quantum noise limit with this squeezed light. Moreover, we measure about -2.2±0.2dB spatial squeezing and reduce the minimum measurable displacement from 1.17A to 0.99A with the signal-to-noise ratio normalized to 1.展开更多
Electromagnetically-induced transparency is observed in a three-level multi-V-type system in cesium vapour at room temperature.The absorption property is measured and the hyperfine structures of atomic states can be d...Electromagnetically-induced transparency is observed in a three-level multi-V-type system in cesium vapour at room temperature.The absorption property is measured and the hyperfine structures of atomic states can be datermined.The results of the experiment agree with the theoretical analysis.展开更多
The direct measurement of the Mandel para- meter of weak laser pulses, with 10 ns pulse duration time and the mean number of photon per pulsenbeing approxi-mately 0.1, is investigated by recording every photocount eve...The direct measurement of the Mandel para- meter of weak laser pulses, with 10 ns pulse duration time and the mean number of photon per pulsenbeing approxi-mately 0.1, is investigated by recording every photocount event. With the Hanbury Brown and Twiss detection scheme, and not more than one photon per pulse being detected dur-ing the sample time by single-photon counters, we have found that the single mode diode laser with driving current lower than the threshold yields a sub-Poissonian statistics. In addition, when the diode laser driving current is much higher than the threshold, it is validated that the Mandel parameter QC of the Poissonian coherent state is nearly -/2.nThe experimental results are in good agreement with theoretical prediction considering the measurement error.展开更多
基金Supported by the National Basic Research Program of China under Grant No 2010CB923102, the Project for Excellent Research Team of China under Grant No 61121064, and the National Natural Science Foundation of China under Grant Nos 11274212 and 11174189.
文摘We experimentally generate a spatially squeezed light beam and realize a small-displacement measurement beyond the quantum noise limit with this squeezed light. Moreover, we measure about -2.2±0.2dB spatial squeezing and reduce the minimum measurable displacement from 1.17A to 0.99A with the signal-to-noise ratio normalized to 1.
文摘Electromagnetically-induced transparency is observed in a three-level multi-V-type system in cesium vapour at room temperature.The absorption property is measured and the hyperfine structures of atomic states can be datermined.The results of the experiment agree with the theoretical analysis.
文摘The direct measurement of the Mandel para- meter of weak laser pulses, with 10 ns pulse duration time and the mean number of photon per pulsenbeing approxi-mately 0.1, is investigated by recording every photocount event. With the Hanbury Brown and Twiss detection scheme, and not more than one photon per pulse being detected dur-ing the sample time by single-photon counters, we have found that the single mode diode laser with driving current lower than the threshold yields a sub-Poissonian statistics. In addition, when the diode laser driving current is much higher than the threshold, it is validated that the Mandel parameter QC of the Poissonian coherent state is nearly -/2.nThe experimental results are in good agreement with theoretical prediction considering the measurement error.
