TRANSMISSION THROUGH A MANY-CHANNEL RANDOM WAVE-GUIDE WITH ABSORPTION

We compute the statistical distribution of the transmittance of a rand om waveguide with absorption in the limit of many propagating channels . We consider the average and fluctuations of the conductance T=tr t d agger t, where t is the transmission matrix, the density of transmissi on eigenvalues tau (the eigenvalues of t dagger t), and the distributi on of the plane-wave transmittances T-a and T-ab. For weak absorption (length L smaller than the exponential absorption length xi(a)), we co mpute moments of the distributions, while for strong absorption (L muc h greater than xi(a)), we can find the complete distributions. Our fin dings explain recent experiments on the transmittance of random wavegu ides by Stoytchev and Genack [Phys. Rev. Lett. 79, 309 (1997)]. [S0163 -1829(98)029 17-8].