Novel materials have emerged as candidates to realize non-volatile memory devices for in-memory computing. This dissertation employs linear and non-linear optical techniques to study the properties of these materials and devices. First, using the optical second harmonic generation polarimetry, we demonstrate that the Neel order in both bulk and thin film NiO and MnN, can be imaged. Then, we apply this technique to study the operational principles of a antiferromagnetic spin torque switching device. Second, using linear magneto-optical Kerr effect, we measure the spin transport properties of an altermagnetic material, RuO2, coming from spin-splitter effect and identify the domain structures, which has not been explored. Finally, the nonlinear optical and ferroelectric properties of AlScN and AlBN, which are promising candidates for realizing both ferroelectric memories and nonlinear photonic devices, are studied.