can anyone help me to demodulate the reflected laser wave and reproduce the audio signal? i was kind of hoping to do this as my project.any kind of help would be appreciated
It works really good... In the movies... 
Have you read [u]Wikipedia[/u] or done any other research?
Wikipedia:
The minute differences in the distance traveled by the light as it reflects from the vibrating object are detected interferometrically...
...The CIA operatives could not tell what was being said, but they could distinguish individual voices, from each person's unique pitch and tone.