He was colleagues with Claude Shannon and Richard Hamming at Bell Labs.
After post-doctoral work at the University of Cambridge and University of Sorbonne, he worked at the Mathematics Research Center at Bell Telephone Laboratories, where he pioneered work in algebraic coding theory on group codes, first published in the paper A Class of Binary Signaling Alphabets.
Here, he also worked along with other information theory giants such as Claude Shannon and Richard Hamming.
Pollak[2][3][4][5][6] on discrete prolate spheroidal wave functions and sequences (DPSWF, DPSS) eventually led to the naming of the sequences as Slepian functions or "Slepians".
This work was fundamental to the development of the multitaper, where the discrete form are used as an integral component.