We propose a novel type of cavity design to generate single longitudinal mode laser known as LOPUT cavity. LOPUT cavity stands for linear orthogonally polarized modes resulting in unidirectional travelling wave cavity. The technique can be applied to both isotropic as well as anisotropic gain mediums. In the present paper, we applied the technique to anisotropic gain medium such as a-cut Nd:YVO₄. Using the LOPUT cavity, we demonstrated nearly 2 W of single longitudinal mode laser with nearly diffraction-limited spatial profile. Linewidth measurement using a custom-made Fabry Perot interferometer revealed instrument-limited linewidth of ∼5 MHz at 1064 nm.