Study On Phase Shifts And Frequency Shifts In Atom Optics

The phase shifts on reflection can be introduced when the laser incidents into the optical components, which will change the pulse shape, have impact on the precision measurement, so carrying on the comprehensive theoretical and experimental researches on the phase shifts introduced by the optical components have very important significance. In the optical lattice clock, because of existing the magic wavelength, the first-order frequency shift of the clock transition cancels, but the frequency shifts due to the hyperpolarizability of atomic clock transitions, magnetic-dipole and electric-quadrupole transitions will not vanish, so they will be the main factors that limit the accuracy of these optical clocks. So making theoretical analyses in detail on the frequency shifts caused by these factors has very important significance for achieving more accuracy optical clock. On the other hand, the frequency stabilized laser is necessary precondition for achieving the accuracy optical clock, there for, we developed theoretical and experimental research on the frequency stabilization of Ti:sapphire lasers at 759nm based on Pound-Drever-Hall(PDH) technique.First, this thesis has detailed theoretical study on the phase shifts produced by the optical components, includes three cases:no coating film on the surface of the optical component, coating dielectric film, coating metal film. We have specifically analyzed the incident angle, the refractive index of the optical component, the refractive index of the film, the thickness of the film on the impact of the phase shifts in the coating dielectric film conditions. We have analyzed specifically sensitive change of reflection coefficient and phase shifts on reflection near the surface plasma resonance in the coating metal film conditions. Based on the phase shift compensated technique, we present a simple and easy method to measure the phase shift induced by the optical component, and specifically, we measured the phase shift on reflection induced by the prism, the experimental result is in accordance with the theoretical prediction.Then, this paper has researched frequency shifts for forbidden J=O→J= 0 clock transitions in the optical lattice clock. At the magic wavelength, the first-order shift introduced by electric-dipole transitions vanishes, but the magnetic-dipole and electric-quadrupole transitions have spatial dependence in an optical lattice that differs from electric-dipole transitions. In combination with the residual translational motion of atoms in an optical lattice, this spatial mismatch leads to frequency shifts which are proportional to the square-root of the field intensity. The magic wavelength for the optical clock transition nearly meets the two-photon resonance conditions, the frequency shift due to hyperpolarizability of atomic clock transitions is proportional to square of the intensity, which depends on the frequency and the polarization. In addition, we have analyzed the second-order frequency shift due to the hyperpolarizability of Yb atomic clock transitions in detail.In order to provide the frequency stabilized lasers for optical lattice clock, we established the laser frequency stabilizing system using PDH technique, introduced the principle and characteristic of PDH technique, and studied the measurement schemes of some key parameters in the laser frequency stabilizing system. Experimentally, we locked the Ti:sapphire laser on 759nm laser frequency, obtained the dispersion signal and locked error signal.