Richard L. Panock

Hyperfine-induced singlet-triplet mixing in 3He

Abstract We report complete determination of the hyperfine structure of 2 3 P and 3 3 D states of 3 He in which significant singlet- triplet mixing is observed. This mixing arises from the hyperfine interaction of the 1s open shell electron. The interaction is essentially independent of the outer electron; thus unlike the case of one electron-like spectra, the hyperfine interaction is crucial to the electronic structure of highly excited states. Our results allow accurate predictions of the structure of these states.

An experimental low-loss single-wavelength bidirectional lightwave link

We describe the perofrmance of a low-loss couplerless bi-directional transmission experiment which operates at a single wavelength. The system is unique in that it employs an annular In0.53Ga0.47As/InP photodetector and has potential for use for both long-wavelength (\lambda < 1.7 \mum) and short-wavelength (\lambda \geq 0.82\mum) transmission. We find that the optical crosstalk between the near-end transmitter and receiver is as low as -16.6 dB (-33.2 dB electrical) for a 200-m link: a value acceptable for use in many short haul system applications.

Optical Second Harmonic Generation by a Single Laser Beam in an Isotropic Medium

We have observed optical second harmonic generation (SHG) in sodium vapor, in the absence of any external fields, using a single input laser beam tuned near either the allowed 3s-4d two photon transition or the dipole-forbidden 3s-5p two-photon transition. In both cases a tunable doubling of the laser was observed with surprisingly large conversion (10−5 to 10−6). When the laser was tuned to the allowed 3s-5p two-photon transition, no doubling was observed. In this paper we present the results of our experimental investigations of these phenomena, and discuss the results in the context of proposed theoretical models for the effect.

Optical SHG in atomic sodium

intensity on the external actions have been found in static experiment. This enabled us to obtain dynamic control of laser characteristics: periodical sweeping of oscillation frequency and cavity Qswitch operation when the laser emits regular spikes at rates up to 50 kHz or giant pulses. The performed experiments have shown as well the possibilities of obtaining mode-locking operation in a fiber laser and, in particular, kinematic mode-locking. Fiber-cavity lasers can find application in optical data transmission and processing systems as sensors of mechanical, thermal, and some other physical quantities and in studies of fiber mode properties. (13 min) 1. R. T. Hawkins, H. Egger. J. Bokor, and C. K. Rhodes. Appl. Phys. Lett. 36, 391 (1980). 2. H. Egger, T. Srinivasan, K. Hohla, H. Scheingraber, C. R. Vidal, H. Pummer, and C. K. Rhodes, A Tunable, Ufrahigh Spectral Brightness ArF * Excimer Laser Source, to be published. 3. H. Egger, R. T. Hawkins, J. Bokor, H. Pummer, M. Rothschild. and C. K. Rhodes, Opt. Lett. 5, 282 (1980). 4. M. Rothschild. H. Egger, R. T. Hawkins, J. Bokor, H. Pummer, and C. K. Rhodes, Phys. Rev. A: 23, 206 (1981). 5. H. Puell, H. Scheingraber, and C. R. Vidal, Phys. Rev. A: 22, 1165 (1980). 6. J. Berkowitz, Photoabsorption, Photoionization and Photoelectron Spectroscopy (Academic, New York, 1979). 7. D. W. Lynch, in Synchrotron Radiation, C. Kunz, Ed. (Springer, Berlin, 1979), p. 357.