Fame
Famous polygraph examiners through history: Let's see. There was, ummm, no one. That's right. Nada. Nien. Zero. Zippo.
However, you could be using your "forensic psycho-psychology" on some famous people like Jack Trimarco, whose webpage motto is "Polygraph Services: When you need to impress someone with the truth."
Perhaps you'll take part in a headline-making trial. But most of your work will be done behind closed doors, with everyone none the wiser.