Showing papers by "James D. Cresser published in 1982"

Resonance Fluorescence of Atoms in Strong Monochromatic Laser Fields

Abstract: The investigation of atomic resonance fluorescence has always been of special interest as a means for the determination of atomic parameters. In addition, information on the interaction mechanism between atoms and radiation can be obtained. In the standard fluorescence experiment the frequency distribution of the incident photons is larger than the natural width of the respective transition; as a consequence the correlation time in the photon-atom interaction is determined by the lifetime of the atoms in the excited state. With the development of lasers and especially of tunable dye lasers in recent years it became possible to study the case where the incident radiation has a spectral distribution which is narrower than the natural width. This corresponds to a correlation time of the incoming light wave which is much longer than the excited-state lifetime. In this chapter a survey of experiments on the resonance fluorescence of atoms in monochromatic laser fields will be given.

Quantum noise in ring-laser gyros. II. Numerical results

Abstract: This is the second of three papers dealing with the effects of quantum noise on the operation of a ring-laser gyro. Exact expressions for the spectrum and the mean beat frequency of the beat signal are obtained in terms of infinite continued fractions. The spectrum is found to be always separable into a "coherent" $\ensuremath{\delta}$-function contribution at zero frequency, representing the effects of locking, and an "incoherent" part of nonzero band-width. Computed forms for the spectrum and the frequency response curve are presented for parameter values appropriate to the ring-laser gyro. The results obtained show that for laser rotation rates corresponding to the locked zone in the absence of noise, the tendency for locking as measured by the strength of the coherent contribution continues to dominate, but this effect rapidly becomes negligibly small outside this zone. In addition, the transition in beat frequency between the locked and unlocked zones which is discontinuous in the noise-free case ceases to be well defined in the presence of noise. Finally, the higher harmonics predicted to occur in the unlocked zone in the absence of noise are found to reoccur in the presence of noise except that the individual harmonics are now found to be broadened.