Magnetooptics of gas lasers

Numerical model for pulsations in polarization of emission from a laser with an anisotropic cavity when initiated in a magnetic field

“…Let us first consider the familiar pattern arising in the case when the magnetic field is turned on after the steady-state polarization of the laser is established. In this case, two variants are possible: 1) if the magnetic field (directed along the axis of the cavity) is higher than some value (the "critical field"), so that the circular phase anisotropy of the laser medium created by the magnetic field is greater than the linear absorption anisotropy of the cavity ⏐r z ⏐ > ⏐h x ⏐, then the plane of polarization of the laser emission is rotated (the Faraday effect) [5,[9][10][11][12][13][14][15][16][17][18][19][20][21]; 2) if the magnetic field is smaller than the critical field, so that the circular anisotropy is smaller than the linear absorption anisotropy ⏐r z ⏐ < ⏐h x ⏐, then the plane of polarization of the emission is rotated by some angle and stops.…”

“…Magnetooptic phenomena, discovered back in the 19th Century [1-3], have attracted attention of researchers even today [4] because of their broad application in optics, laser physics [5,6], and also for high-current polarization measurements [7]. In this paper, we demonstrate the possibility that there is one more interesting magnetooptic effect which can be used to control the polarization properties of laser radiation.…”

“…This effect has been well studied both experimentally and theoretically [5,6,[9][10][11][12][13][14][15][16][17][18][19]. One of the many applications of this effect is measurement of small magnetic fields (laser magnetometry) [20,21].…”

“…The indicated problem cannot be solved on the basis of the equation for the electromagnetic field amplitude in a laser cavity [5,[15][16][17][18], or within the physically equivalent formalism with transmission and reflection matrices [19,23], since in these approaches the emission is assumed to be completely polarized. We need an approach allowing us to describe partially polarized laser emission, and specifically we need equations determining the evolution of the polarization density matrix [24][25][26].…”

“…Equation (1) can be more rigorously derived [5,[15][16][17][18]. Furthermore, absorption of radiation in the mirrors of the cavity and the gain of the laser medium can be formally included in the refractive index ∆n by adding an imaginary value to it:…”