Method Of Separated Fields Research Articles

Transitions induites par deux impulsions — Spectroscopie par transformée de Fourier

The transition probability induced between two energy levels, by two electrical pulses, is studied. The experimental method uses a H 2 CO molecular beam apparatus. It is shown that the spectrum is the Fourier Transform (TF) of the transition probability obtained by scanning the delay between both pulses. This method is an extension of the Ramsey method of separated fields; because the carrier frequency is zero, there is no Bloch Siegert shift. When the pulses are not rectangular, it is shown that the method is still applicable in the sudden approximation

Collision-induced Ramsey resonances in Sm vapor.

Ramsey’s method of separated fields for the observation of narrow radiofrequency (rf) resonances is well known from atomic and molecular beam experiments /l /. In this contribution, we demonstrate the occurrence of similar Ramsey resonances in an atomic vapor due to collisional velocity diffusion of sublevel coherence within an optical Doppler distribution; here the velocity diffusion of sublevel coherence between the excitation and detection processes plays a role similar to the spatial motion of the active atoms in conventional Ramsey experiments. The new phenomenon is observed using coherent resonance Raman processes to optically induce and detect Zeeman coherence in the Sm λ=570.68 nm J=1 - J’=0 transition.

Method of separated fields in optics

Three methods are of great importance for super-high resolution spectroscopy and in obtaining supernarrow resonances. These are as follows: the method of saturated absorption, two-photon spectroscopy, and the method of separated optical fields. The first two methods are well known and developed. Recent progress in developing these methods has been discussed in [1]. The narrowest resonances and high resolution were obtained by the method of saturated absorption. It is based on the use of a Lamb dip [2] in an absorption line. The use of absorption saturation resonances has been begun in 1967 with investigations of He-Ne lasers with a Ne absorbent which were independently carried out in Perkin Elmer laboratories [3] and in our institute [4].