J.P. Taché

Lamb dip asymmetry in lasers with plane-parallel resonators

The Lamp dip asymmetry due to linear or nonlinear lenslike effects is investigated in lasers with plane-parallel resonators. The experiments are performed using diffracted light spectroscopy. It is shown that the frequency-dependent diffraction losses are essential in determining Lamb dip asymmetry, regardless of the origin of the lenslike effects.

Off-resonance dispersion profile effect in gas laser resonators.

Diffraction losses and resonant frequencies of a gas laser resonator perturbed by an off-resonance dispersion profile, due to nonuniform radial distribution of excited atoms, are predicted by extending the ray transfer matrix formalism. These predictions are tested experimentally by using the laser beam as a probe. Experiments are done with a 6401-A He-Ne laser. In this case perturbations are induced by the strong neon absorption line at 6402 A. The two studied properties lead to determinations of the population of neon 1S5 metastable level which are both in good agreement, so the validity of the theoretical analysis presented is confirmed. It is also shown that off-resonance dispersion profile effects occur in the 6328-A He-Ne laser.

Reverse Sagnac Effect in Ring Lasers

We report here the possibility of controlling the position of the standing-wave pattern in a ring-laser cavity at rest thanks to diffraction. Modulating the position of the aperture along the beam axis induces a beat frequency between the two counterpropagating waves in the motionless ring laser, the so-called reverse Sagnac effect. This effect permits us to observe rotation rates like the Earths one, several orders of magnitude smaller than the width of the locking region, by purely internal measurements.

Different critical geometries for half-symmetric laser resonators

Abstract It is shown that three different critical geometries can exist for a half-symmetric resonator with an internal lens of variable focal length. Indeed, in addition to the previously demonstrated critical geometry leading to a mode size on the spherical mirror which is stationary with respect to the focal length, two other geometries give a stationary mode size on the plane mirror. An experimental arrangement leads to a verification of the theoretical predictions.

Measurement of g values of atomic levels of neon in a Zeeman laser

Abstract We use the interactions between the α components of a multimode laser, with axial magnetic field to measure the g factor of the 2s 2 level.