LIDAR units could cycle through randomly-generated patterns for each pulse - if they can be made unpredictable then it would be impossible for someone to confuse a LIDAR unit by copying its pulses. Assuming it's a time-of-flight LIDAR then the time required for an attacker to read a pulse and send back their own signal would be greater than the time of the original signal to return - and if the sending LIDAR has a sufficiently short timeout then even an attacker using Vanta-black to absorb all of the victim's lasers still won't be able to respond quickly enough.