You might be surprised at some of the things the amateur radio guys used to build in their garages.
In the "old days" I once got recruited to work on a government contract that required me to get up to speed on microwave RF design very quickly. So in my spare time I got into experimenting with cheap RF gear that I found in advertised in amateur radio magazines. There was a retired microwave engineer who built & sold components for doing all the basic functions for making microwave transmitters, receivers, radars, etc., and I experimented with a lot of his stuff. So I know that you can build RF systems cheaply using box-level components connected by RF cable. What's really hard is building these systems in the miniaturized RF circuit board form factor, where you have to use microstrip design techniques.
Of course you first have to spend a lot of time learning RF stuff, e.g. read the ARRL Handbook cover to cover.
There are some sites run by amateur radio guys that deal with laser communications, and a laser radar is not too much different from a laser transceiver. A laser radar IS a laser transceiver, actually, with a special kind of modulation. You can also look up FMCW radar (FMCW = frequency-modulated continuous-wave), which is what the consumer-type laser rangefinders are.