Quantitative study of open channels by digital holography

Open channels are peculiar incidents modes of the optical field that are transmitted by a highly diffusing medium with high efficiency (100 % in the ideal case). The existence of these modes has been predicted by Dorokhov et al. [1] more than 25 years ago. Although many experiments were made to prepare these modes [2, 3], the maxima of transmission obtained in experiments, are ever much lower than 100 %. To test the theory, we have considered here another Dorokhov's prediction: the average transmission of the modes that sustain the transmitted field must be T
_t
=66%, where Tt is defined by N2 T
_t
= N
₁
T (where T is the averaged transmission of energy, and N
₁
and N
₂
the number of incident and transmitted modes i.e. the size of the incident and transmitted mode basis).