A bolometer is a sensor physically much like a common photographic CMOS or CCD sensor, except that it employs different material, a different transduction process, and is sensitive to a very broad range of electromagnetic energy rather than a relatively restricted range in and around the visible bandwidth.
A microbolometer is a specially configured and very responsive bolometer for use in portable thermal cameras; as the name suggests, a microbolometer is also a physically small version of a more classic bolometer.
Unlike common visible band imaging sensor arrays, a microbolometer does not employ a color filter array such as a Bayer Array; color values assigned to thermograms are computationally generated during in-camera processing or post processing. Electromagnetic energy itself has precisely no color character.
This video (5:55) explores the nature and performance of common microbolometers.