ABSTRACT QUADRATIC ELECTRO-OPTIC BASED DEFLECTION-FREE WIDE PATH-LENGTH MODULATION AND LATERAL SCANNING DEVICE FOR TIME DOMAIN OPTICAL COHERENCE TOMOGRAPHY The TDOCT system is based on quadratic electro-optic effect and involves non-mechanical, noiseless approach. Electro-optic materials exhibit a change in their optical property refractive index under an applied electric field. Potassium Tantalate Niobate (KTa1-xNbxO3, KTN) possesses a large quadratic electro-optic coefficient with a cubic crystalline structure. This allows a wide range optical path-length modulation at high speed slightly above the critical temperature, which is appropriate for TDOCT. Further, when KTN is operated with a slightly lower temperature crystalline phase structure, light propagating through KTN experiences deflection depending upon an application of an electric field. Thus the proposed system is useful for scanning samples in axial and lateral direction without any motion at high speeds (kHz to MHz order). This invention is applicable in the fields of Medical imaging, diagnosing and sensing and metrology applications. This improves the speed of imaging and provides deep imaging for diagnostic application of Time Domain Optical Coherence Tomography system. Most Illustrative Figure: FIG.14