S.R. Hartmann

Frequency shifts in emission and absorption by resonant systems ot two-level atoms☆

Abstract The frequency shifts in emission and absorption arising from resonant many-body interactions in a system of two-level atoms are discussed from several points of view: (1) in the language of superradiance, Dicke states, quantum electrodynamics and perturbation theory; (2) in the classical-path treatment of gaseous emission, with emphasis on the impact approximation; (3) by means of diagrams related to the temperature-Greens function formalism; (4) in the semiclassical model using the macroscopic Bloch vector; (5) through ordinary classical electromagnetic theory in a linear medium.

Prism‐dye laser

A simple continuously tunable laser‐pumped dye laser is described. A dye solution in contact with a lateral face of a right‐triangular 90° prism, adjacent to the 90° corner, is pumped by laser light incident on the lateral face opposite to the 90° corner. A standing‐wave pump field is produced in the dye solution by the interference between the pump light that passes directly to the inner face in contact with the dye solution and the pump light internally reflected from the other lateral face adjacent to the 90° corner. The output wave‐length is determined by the spatial periodicity of the standing‐wave field and is easily varied by changing the angle of incidence between the pump‐laser beam and the prism face.

Superradiant damping and absorption

Abstract We obtain a relationship between the absorption coefficient and the superradiant lifetime which shows that superradiant damping can be large only in an optically thick sample. Accordingly, we reexamine the recent photon-echo experiment of Compaan and Abella.

Limited superradiant damping of small samples

We show that for samples small compared to a wavelength the maximum possible superradiant damping is severely limited by the shortness of the radiation-field-induced relaxation time TΔ as compared to the superradiant lifetime TS.

Radiation locked photon echoes and optical free induction in ruby

Abstract We report the first observation of the radiation locked photon echo and optical free induction in ruby. The initial time behavior of the free induction when produced by a long pulse is examined.

Photon Echo-Nuclear Double Resonance (PENDOR) in ruby☆

Abstract PENDOR spectra in ruby have been obtained and analyzed tielding CrAl interaction parameters associated with Al nuclei near Cr3+ ions for Cr3+ in E (2E) optically excited state.

Photon echoes in CaWO4:Nd3+☆

Abstract We report the generation and detection of photon echoes in CaWO 4 :Nd 3+ . We also describe photon echo behavior as a function of an applied magnetic field and of temperature.

Evidence of a photon echo-nuclear double resonance in ruby☆

Abstract We report the degradation of stimulated photon echoes in ruby by the application of an rf field at frequencies corresponding to nuclear spin transitions of Al neighbors of a Cr 3+ ion.

Frequency shifts in resonant systems

Abstract We calculate the frequency shift due to resonant interaction between identical radiating atoms. We give numerical results for particular geometries. In some cases the shift exceeds 1 10 of the pressure-broadened width. We indicate that these results are valid in absorption as well.

Spontaneous Raman scattering in atomic thallium vapor

Abstract Using a cw argon-ion laser, we have measured the spontaneous Raman scattering cross section, σ R , and linewidth in atomic thallium vapor. For 4880-A excitation, σ R = 1.6 × 10 −27 cm 2 . We observe no pressure broadening of the Raman line at vapor pressures to 100 torr.