Nonreciprocal phase shift has been predicted and observed in a fiber-optic gyroscope based on a Sagnac interferometer when the intensities of the counterpropagating beams are unequal. The magnitude of this intensity-induced phase shift is 1.4 rad/W power difference. At 1-microW power difference, this is equivalent to a rotation rate of 0.2 degrees /h in our 200-m-long fiber with a core radius of 2.25 microm that is wound around a spool of 19-cm diameter. The data are consistent with theoretical predictions based on four-wave mixing in the quartz fiber.

We demonstrate the generation of the time-reversed replica of an incident monochromatic image-bearing optical beam that is nonuniformly polarized. A form cf degenerate four-wave mixing in liquid CS2 of beams at 532 nm is employed. We discuss sources of distortion in the vector replica using standard theory of nonlinear beam interaction.

When a Raman active material is placed inside the optical Fabry-Perot cavity resonator of a giant pulse ("Q-switched") laser, the high-power laser light pulse induces gain in the Raman material at frequencies shifted from the giant pulse frequency by well-known Raman frequencies. If this gain is large enough to overcome cavity losses, a strong buildup of coherent light at the shifted frequency(s) may ensue; the process is analogous to stimulated fluorescence and is an example of stimulated Raman scattering. We calculate here the Raman output power as a function of time and its spectral content when the Raman material is in the laser cavity. From the resulting expressions (which contain no undetermined parameters) we calculate the properties of the light generated by nitrobenzene inside a giant pulse ruby laser and find that the results agree with (as yet incomplete) observations that have been made on that system.

A method of laser modulation is described which produces fast, intense and controllable "giant" laser pulses by "Q-modulation." In experiments with ruby, pulses of peak power up to 15 MW and of duration less than 30 nsec have been studied. The principles of the technique are outlined and early experimental results reviewed. The temporal, spectral and spatial structure of giant pulses produced from...

An atomic-beam apparatus is described with which the nuclear spin and hyperfine structure separation of the ground state of the radioactive isotope 11147Ag have been found. The nuclear spin is I = 12, in agreement with the result of McGinnis and of Lemonick and Pipkin. The other experimental results are: Δν(111Ag) = 2204.54 ± 0.05 Mc/s, gJ(Ag) = 2.00235 ± 0.00012, μI(111Ag) = -0.145 ± 1% nuclear magnetons.

In magnetic resonance experiments with atomic beams an atom is often exposed to a radio-frequency field whose amplitude varies along the path of the beam. To obtain an estimate of the shape of the resonance line to be expected with various radio-frequency loops, the Fourier transform of a function resembling the amplitude of the radio-frequency field has been taken in each case. These transforms are compared with experimental curves, and qualitative agreement is found.