# How to maximize the modulation depth?

Suppose I am modulating a laser beam of a particular wavelength using AOMs. How do I ensure that I have achieved 100 % or the maximum possible modulation depth? My laser is 80 MHz rep rate laser and I am modulating it at a much lower frequency say 1MHz. I can observe the beats using a oscilloscope though.

In a practical manner: The modulation depth, $M_d$ was then calculated at each ultrasound pressure using:
$$M_d=\frac{{modulated},{light}}{{total},{intensity}, {light}}$$