Spy conversation with laser from remote distance

Some circuit design and expirience for spying with laser beam?

Base concept:
Laser beam detect oscilations in remote glass of window then signal amplifies and we hear remote conversation.

I have some circuits founded on Internet, but i interested for people with expirience on that field.

Some partial examples on that theme:

I would get in touch with the KGB as they have field use of such kit, using it on the American embassy in Moscow.
frank

Of course I found this nice toys on net for selling but price is somehow how to told "warm my ears". Of course russian toys.

I saw some of DIY on net, but noise is present, and I looking some expirience advice and suggestions.

To make clear, I'm not spy, just this is interested theme. I like things like that.

Probably fbi, cia, mia, kia is on the way to my house.