For those interested:

The foundations of this technology were explored by Italian researchers in 2012 who actually began their efforts by calculating the effects that a black hole will have upon the angular momentum of light as it passes by.

Here is an article going into more detail: http://physicsworld.com/cws/article/news/2012/mar/07/physicists-put-a-new-twist-on-radio

Here's the study: http://iopscience.iop.org/article/10.1088/1367-2630/14/3/033001;jsessionid=BD40605885042A6010843FFAE3327328.c3.iopscience.cld.iop.org