A gravity-enforced photon momentum radiometer incudes: a magnetic array; a diamagnetic shuttle that levitates above the magnetic array; a mirror on the diamagnetic shuttle that receives laser light and moves the diamagnetic shuttle due to the optical force; a tiltable platform for the magnetic array; a photogate producing gate light that can be blocked by a photo interrupter and that produces a detector signal that provides a position of the diamagnetic shuttle relative to the tiltable platform for determining a position of the diamagnetic shuttle relative to the photogate.