Total internal reflection yag rods usage thereof

By accident found a patent with one of these rods in use? see link if you dare!

http://www.google.com/patents?id=hu0...cavity#PPA7,M1

Blip....Blip..... Blip yes there is a weak pulse in here somewhere!

I have acquired two they are supposedly military surplus. They are 5x5x 75mm and have dual inclined ends about 30 degrees non parallel.

It is my recent understanding that some of these style rods utilize dual side pumping via diode lasers, however these? might have originally have been arc or flashlamp pumped. I would love to know their original military application, a safe guess might be a second generation laser range finder possibly an eye safe wavelength

I am hoping birefringence (learned how to spell that correctly from patent whoops!) issues are reduced since the laser energy does not make a straight pass through these type rods but instead is supposed to bounce its way down the length of the rod, thus the term "Frustrated" is used to describe these type YAG Rods

Follow up: Yes my suspicions about birefringence were confirmed to be correct , another apparent advantage of this design can be updoped rod ends to further reduce these issues. another apparent advantage is that the multiple rebounds side to side allow for greater pumping efficiencies.