Ultra-broadband White Light Cavity Based On Color Center System In Diamond

In recent years,with the rapid development of broadband optical communication and high sensitivity detection,white light cavity(WLC)has caused great concern of scientific researchers.The so-called WLC is a traditional Fabry-Pérot cavity filled with a kind of medium which provides negative dispersion and eliminates the frequency dependence of phase delay,and produces broadband resonance in the continuous frequency range.Based on the unique advantages of WLC itself,it has been proposed for various applications.It is well known that precision measuring instruments such as gravitational wave detectors and ring laser gyroscopes require high sensitivity,and we know that to achieve high sensitivity requires highly refined Fabry-Pérot cavity,which usually loses bandwidth.The WLC provides an effective way to solve this problem.Therefore,more and more attempts are made by researchers to realize white light cavities from experimental and theoretical perspectives,such as four-wave mixing,double dark resonance system,nonlinear dispersion and stimulated Brillouin scattering in optical fiber.However,the bandwidth of these schemes to realize WLC is kept at the order of MHz,which limits the application of WLC to a certain extent.In order to better apply the WLC to various fields in the future,this dissertation provides two new schemes to realize the WLC.The first scheme is to improving the existing traditional three level ? atomic system.A better scheme of two-color coupled equivalent four level system to realize the WLC is proposed,which effectively reduced the intensity of the driving field and the difficulty of realizing the WLC in the experiment.In addition,we also propose a scheme to construct a WLC in which diamond NV color center is filled in the Fabry-Pérot cavity to obtain GHz order of magnitude broadband.With the first scheme,we adopt the two-color coupling mechanism to realize WLC based on the original scheme of three level ? atomic gas.Then the total polarizability of the system is superimposed by the nonlinear polarizability generated by Raman process and linear polarizability,the nonlinear polarizability compensates the original linear polarizability to a certain extent.Under the condition that the range of transparent window remains unchanged,the slope of dispersion is reduced without causing other changes as far as possible.Therefore,the WLC can be obtained with a smaller driving field intensity by selecting appropriate parameters on the premise of ensuring no obvious change in bandwidth.For the second scheme,due to the energy level structure and optical properties of the diamond NV color center is similared to the atomic system,and compared with the atomic system,the structure of solid system is compact,the performance is stable and the antiinterference is strong,so we propose to use the NV color center to construct the WLC in the Fabry-Pérot cavity.Firstly,the negative dispersion is achieved by adjusting the incoherent pumping rate and the driving field intensity in a relatively wide transparent window.Then,the driving field intensity satisfying the condition of WLC is obtained by numerical method.Unlike the three-level ? energy level structure of atoms,the NV color center needs to consider inhomogeneous broadening,which is caused by the difference of local fields in different locations.Therefore,in this dissertation,after using numerical method to calculate the Gaussian integral for the inhomogeneous broadening of two different energy levels,the condition of the WLC of the system is analyzed and discussed,and the conclusion that the ultra-broadband WLC can be achieved in theory is drawn.And we also discuss the broadband optical switch based on WLC at last,so as to provide technology for the development of the broadband quantum optics reserves.