Collision echo in magnetic field

✍ Scribed by V.A. Reshetov; E.N. Popov; I.V. Yevseyev

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 143 KB
• Volume: 8
• Category: Article
• ISSN: 1612-2011
• DOI: 10.1002/lapl.201010114

✦ Synopsis

The effects of the longitudinal magnetic field on the collision photon echo, which is formed by two laser pulses with orthogonal polarizations on the transition with the angular momentum change J a = 0 → J b = 1 and arises due to the action of the elastic depolarizing collisions, are studied theoretically. It is shown that weak magnetic field acts to diminish the intensity of the collision echo up to zero, providing the tools for measuring the relaxation rates due to such collisions. With the further increase of the magnetic field strength the echo intensity reveals almost pure harmonic oscillations, though in strong magnetic field the echo appears not due to the action of collisions but mainly due to the action of the magnetic field, so it becomes not collision but conventional photon echo. However the comparison of the amplitudes of the collision echo in zero magnetic field with the maximum echo amplitude in strong magnetic field yields one more way to measure the relaxation rates due to elastic depolarizing collisions. 0.5 1.0 0 0.20 0.15 0.10 0 0.05 Dimensionless splitting frequency s Amplitude ratio e(s)/e(0)

The dependence of the ratio e(s)/e(0) of amplitudes of collision echo in weak magnetic field and in zero field versus the dimensionless parameter s = g b μBH/hγ proportional to the magnetic field strength H, where μ B is the Bohr magneton, g b is the Lande factor of the upper level and γ is the homogeneous half-width of the resonant spectral line