Kassahun, Fesseha (PhD)Alemu, Menisha2019-10-082023-11-092019-10-082023-11-092018-09-03http://10.90.10.223:4000/handle/123456789/19323In this PhD dissertation we have studied the statistical and squeezing properties of the cavity light generated by a three-level laser. In this quantum optical system, N three-level atoms available in an open cavity, coupled to a two-mode vacuum reservoir, are pumped to the top level by means of electron bombardment at constant rate. We have considered the case in which the three-level atoms and the cavity modes interact with the two-mode vacuum reservoir. We have carried out our analysis by putting the noise operators associated with the vacuum reservoir in arbitrary order. Applying the solutions of the equations of evolution for the expectation values of the atomic operators and the quantum Langevin equations for the cavity mode operators, we have calculated the mean and variance of the photon number as well as the quadrature squeezing for the cavity light. In addition, we have shown that the presence of the spontaneous emission process leads to a decrease in the mean and variance of the photon number. We have seen that the global mean photon numbers of the light modes emitted from the top and intermediate levels are the same both in the presence and absence of spontaneous emission, and are separately in a chaotic state. However, we have observed that the two-mode cavity light is in a squeezed state and the squeezing occurs in the minus quadrature. In addition, we have found that the effect of the vacuum reservoir noise is to increase the photon-number variance and to decrease the quadrature squeezing of the cavity light. However, the vacuum reservoir noise does not have any effect on the mean iii iv photon number. Moreover, the maximum quadrature squeezing of the light generated by the laser, operating far below threshold, is found to be 37:5% below the vacuum-state level. In addition, our result indicates that the quadrature squeezing is greater for = 0 than that for = 0:4 for 0.01 < ra < 0.35 and is smaller for = 0 than that for = 0:4 for 0.35 < ra < 1. We have also noted that the local quadrature squeezing approaches the global quadrature squeezing as the frequency interval increases. Furthermore, applying the density operator for a pair of superposed two- mode laser light beams, we have calculated the mean and variance of the photon number as well as the quadrature squeezing. We have found that both the mean photon number and the quadrature variance for the superposed two-mode laser light beams is the sum of the mean photon numbers and the quadrature variances of the constituent two-mode light beams. However, the variance of the photon number of the superposed two-mode laser light beams is not the sum of the variances of the photon numbers of the constituent two-mode light beams. Finally, our result shows that the quadrature squeezing of the superposed two-mode laser light beams is equal to the quadrature squeezing of one of the superposed the two-mode light beams. This implies that the superposition of the two-mode laser light beams does not affect the quadrature squeezing, but it increases the global mean photon number and the global variance of the photon number. Thus we note that the superposition of the two-mode laser light beams leads to a more bright squeezed light.enDynamics of three-Level LaserPumpedElectron BombardmentSpontaneousEmissionThesis