The Design Of Quantum Imaging System With Squeezed Light And The Research Of Modularization Of Prototype

Laser light is notable for its high degree of spatial and temporal coherence, unattainableusing other technologies. Laser beams can be focused to very tiny spots, achieving a veryhigh irradiance or they can be launched into a beam of very low divergence in order toconcentrate their power at a large distance and so is applied widely in nowadays engineering,agriculture, medicine, remote probing and non-invasive detection. Lasers are the lightsources in all quantum optics experiments, but they are far from ideal; most lasers haveintensity noise well above the quantum noise limit (QNL). To improve signal-to-noise ratios,squeezed state, a non-classical state, is paid more and more attention due to their ability toreduce quantum noise to below the vacuum noise level. With this advantage of it, thesqueezed states of light are widely applied in precision optical measurements and opticalcommunication. Also the squeezed states of light and correlated photon pairs are used todemonstrate the Einstein-Podolsky-Rosen (EPR) paradox, for the generation of Schr dingercat states for quantum information networks and as a resource for quantum teleportation.However, the use of squeezed light to improve the imaging resolution in the imaging processis rather limited.In this paper, this amplitude squeezed light with its higher signal-to-noise ratios thantraditional laser light was generated by utilizing the nondegenerate optical parametricamplifier (NOPA) based on periodically poled KTiOPO4(PPKTP) crystal at1064nm. Inorder to observe high level of squeezing, the entire experiment was optimized for low phasefuctuations. Balanced homodyne detection was employed to observe the generated squeezedstates and get a result of a classical noise reduction of4.93dB below the shot noise. Theimaging experiments of resolution target have shown that the imaging resolution, which wasbased on squeezed state light, is1.41times as much as the resolution that was acquired usingcoherent light as light source, and we have also verified that as the noise reduction increasedthe imaging resolution improved more.In addition, the squeezed state light was applied for imaging of virtual object. It wasfound that the characters on the board were much more easily discerned with squeezed lightas a light source than with coherent light as light source. This result paves the way for furtherimprovements of imaging resolution by the use of the squeezed state light. Meanwhile, thedegree of squeezing was simulated theoretically to find out the relationship between somefactors and the degree of squeezing. In this way, the results could guide the experiment toacquire a better degree of squeezing. To facilitate the stability of imaging, we designed anoptical system and modularized it in a small-scale portable optical system module. Themodule was composed of an optimized optical system and a low-light-level imagingintensifer. The modularization of imaging system is a portion of the modularization ofamplitude squeezed light laser active imaging, and a foundation of the design of squeezedlight laser active imaging camera. In the end, preliminary system of the modularization ofprototype of imaging with squeezed light was suggested. This paved the way for the follow-up researches.