Showing papers on "Light field published in 1969"

Correlations in Light from a Laser at Threshold

Abstract: Temporal correlations in light field from laser at threshold of oscillation, measuring He-Ne CW gas laser by photoelectron count

Theoretical Dependence of the Near-Asymptotic Apparent Optical Properties on the Inherent Optical Properties of Sea Water*

Abstract: The apparent optical properties of sea water are a set of measurables that describe the geometry of the submarine light field. These properties are related to the inherent optical properties—the volume attenuation coefficient and the volume scattering function—through the process of radiative transfer. A numerical approximation to the equation of radiative transfer was programmed for solution on a high-speed digital computer. The technique is based on resolving the hydrosol into a system of thin slabs, finding approximate transmission and reflection operators for each slab, and then systematically applying these operators to determine the geometry of the light field in the interior of the system of slabs. Thus each set of calculations produces the radiance solid as a function of depth. The apparent optical properties were found by numerical integration of the radiance. A simple three-parameter model was used to simplify study of the dependence of the apparent optical properties on the directional characteristics of the volume scattering function.

Visualization of a coherent light field by heterodyning with a scanning laser beam.

Abstract: This paper discusses a sampling method of optical holography in which the received phase and amplitude information about any arbitrary cross section of a light field is electronically processed and displayed on a TV monitor. Because the technique makes it possible to discriminate between optical signals with a small frequency difference it should be a useful tool in those methods which investigate acoustic phenomena by dynamic scattering of light. In particular, the application to real time acoustic holography is discussed. Experimental results are presented showing the intensity distribution of both statistically and dynamically scattered optical fields.

On pressure broadening in a He-Ne laser

Abstract: Evidence of the combined influence of disaligning and velocity-changing collisions on laser light-induced saturation peaks or holes in the velocity distribution of Ne 2p_{4} atoms was obtained by transmitting 1.15-μ light of a short single-mode He-Ne laser through the discharge tube of a long single-mode Michelson interferometer-type He-Ne laser oscillating at 0.63 μ, and by measuring the frequency-dependent single pass gain of the IR light in the discharge of the latter laser. Atoms that have undergone a transition in the linearly polarized red-laser light field are partially aligned. The width of the detected signal depends on the He gas pressure and also on the mutual polarization of the two laser fields. This indicates a smaller velocity broadening for aligned atoms than for collisionally disaligned ones. An evaluation of the data provides information on the correlation of the above-mentioned collision processes and on phase-disturbing and phase-nondisturbing contributions to the line broadening. Estimate values of the integral elastic Ne 2p_{4} -He scattering cross section and a cross section for phase shifting collisions are given.

Photographic printing of cathode-ray tube screen structure

Abstract: During the fabrication of a cathode-ray tube screen structure, a light field is projected through a photographic master, a correction lens and an optical filter incident upon a photosensitive layer. The filter is a relief image comprised of preformed, nonmetallic, light-absorbing particles having a mean diameter in the range of 5 to 50 millimicrons in a lighttransmitting binder. The filter has variations in light transmittance which produce predetermined variations in light intensity in the light filed tailored to the particular system.

On the origin of laser coherence

Abstract: It is shown that the light created in the process of the “emission of many photons by many atoms”, as treated recently by Ernst and Stehle, has extreme coherence properties. In particular, it leads to spatial interference effects between radiation from two distinct sources of this type. Under certain conditions this interference even can become optimal in the sense that the intensity minima vanish. Furthermore, in the sense of the definition of Glauber, the light field produced in this process is practically coherent to the ordern∼N, whereN is the the number of emitted photons. One arrives at a natural and simple interpretation of two-laser interference experiments of Magyar and Mandel, and Pfleegor and Mandel, if one assumes that the mentioned process constitutes the primary creation mechanism of laser light. It is shown that and how the physically important features of laser activity can be understood on the base of this assumption.

Visualization of a coherent light field by heterodyning with a scanning laser beam

Abstract: This paper discusses a sampling method of optical holography in which the received phase and amplitude information about any arbitrary cross section of a light field is electronically processed and displayed on a TV monitor. Because the technique makes it possible to discriminate between optical signals with a small frequency difference it should be a useful tool in those methods which investigate acoustic phenomena by dynamic scattering of light. In particular, the application to real time acoustic holography is discussed. Experimental results are presented showing the intensity distribution of both statistically and dynamically scattered optical fields.

Acoustical Imaging by Diffracted Light—Two-Dimensional Interaction

Abstract: A formalism is developed describing quantitatively in terms of plane waves the weak interaction of two-dimensional sound and light fields of arbitrary cross-section. This formalism is applied to the analysis of the phenomenon of acoustical imaging by diffracted light demonstrated previously by the author (4).