in photography where these terms are also used, the 3 different light provide diferent effects, as tghey do in microscopy:

top light directly at a right angle onto a flat subject also called frontal light, is even and relatively shadowless.

backlight emphasis the internal structure if the subject is transparent , and also provides particular effectsround the perimeter (not the intention here )

light from the side gives clues to the properties of the surface by emphasising unevenness with shadows.

In this context you could say:
with a facility for illumination from the top,side and behind the object...