A novel directional graphene-based nano-metasurface antenna is proposed for optical frequency applications, featuring optimized gain performance. This bow-tie antenna incorporates a metasurface that acts as a lens. A highly resistive silicon substrate with a dielectric constant of 11.9 is used for simulation. The bow-tie antenna with an H slot in the arm is surrounded by the square-shaped metasurface unit cell, which helps in improving directional property of antenna. Base structure consists of a square substrate measuring 5000 μm in length and 300 μm in height. Lens metasurface is placed in between the 2 bows of the antenna to improve directivity and gain of the antenna, with a total of 15 metasurface lens unit cells placed between the bows. These unit cells work as a reflector. The antenna operates at three resonant frequencies, 0.4 THz, 1 THz, and 2.2 THz, demonstrating triple-band functionality. The maximum achieved gain is 12.5 dBi, with a peak radiation efficiency of 89.7%. All simulations and optimizations were conducted using HFSS 21.0 software.