Potassium tantalate niobate (KTN) crystal-based polarization-modulated 3D ladar with a large field of view

An innovative 3D ladar that utilizes potassium tantalate niobate (KTN) crystal as a polarization modulator is proposed in this Letter. The optical isotropy of KTN in cubic phase can effectively suppress the range errors induced by the incident angles of collected beams in 3D imaging. The giant quadratic electro-optic coefficient can dramatically lower the voltage that is required to modulate the polarization so that a high voltage amplifier with less noise can be used to improve the ranging performances. By virtue of these two advantages, a range error of 4.8 cm and a range precision of 4.4 cm at 15 m have been achieved under a large field of view of 20° (about 0.35 rad) and a maximum detection range without ambiguity of 60 m.