Measurement And Application Of The Squeezed State With A Bichromatic Local Oscillator

Nonlinear optics is an important branch of quantum optics,which mainly studies the nonlinear effects of dielectrics under strong coherent light.Nonlinear optics not only breaks through the linear superposition principle and independent propagation principle in traditional optics,but also reveals the phase correlation and energy conversion of light field in medium.In recent years,the frequency doubling,difference frequency generation,sum frequency generation,stimulated scattering and other nonlinear effects have achieved rapid development with the increasingly mature of laser technology.Especially,the squeezed states,generated by optical nonlinear effect,are paid extensive attention and realized successfully in different physical systems.At the same time,the squeezed states are widely applied to optical precision measurement,quantum state engineering,quantum state storage,quantum communication and quantum computing.In this thesis,we introduce a series of work based on optical parametric amplifiers with PPKTP crystal.We use three acousto-optic modulators to produce double-sidebands around the fundamental frequency,which is served as local oscillator to verify quantum correlation between the upper and lower sideband mode of the squeezed vacuum state.Then the bichromatic local oscillator and squeezed vacuum state are utilized to improve the signal-to-noise ratio of the low-frequency signal measurement.We also inject the singlesideband and double-sidebands into the optical parametric amplifier,and reconstruct the vacuum state,coherent state,squeezed vacuum state,amplitude squeezed state and phase squeezed state with optical homodyne tomography.Moreover,we generate the entangled state by coupling two single-mode squeezed states on a 50/50 beam splitter,and demonstrate the coherent state transfer with partially disembodied transport.We build the semi-monolithic optical parametric amplifier with PPKTP crystal whose front end is used as the input coupling mirror.The length of OPA is locked by Pound-DriverHall technology and the error signal is extracted from the reflected pump field.We use three acousto-optic modulators to produce double-sidebands around the fundamental frequency,which is served as local oscillator to verify quantum correlation between the upper and lower sideband mode of the squeezed vacuum state.We utilize bichromatic local oscillator to detect the squeezed vacuum state,and achieve the maximum conditional squeezing by altering the power ratio of double-sidebands.Moreover,a small portion of lower sideband is used to generate the low-frequency signal,and detected by bichromatic local oscillator together with the squeezed vacuum state.In this way,the sensitivity of low-frequency signal is enhanced with the maximum conditional squeezing.The single-sideband and double-sidebands are used as the signal field of the optical parametric amplifier,whose output is measured by an intense local oscillator with fundamental frequency.We then reconstruct the vacuum state,coherent state,squeezed vacuum state,amplitude squeezed state and phase squeezed state with optical homodyne tomography.We generate the entangled state by coupling two single-mode squeezed states on a 50/50 beam splitter,and demonstrate the coherent state transfer with partially disembodied transport.By controlling the amount of information that is broken during the joint Bell state measurement,the fidelity break through the no-cloning limit with the introducing of semiquantum channel,resulting in a maximum fidelity of 0.9.