Broadband Ultrathin Transmission Quarter Waveplate with Rectangular Hole Array Based on Plasmonic Resonances

The control of the polarization states of light plays an important role in modern optical systems. However, traditional polarization manipulating devices often have narrow bandwidth and their large size makes it difficult for them to achieve miniaturization and integration of optical systems. This work presents an ultrathin quarter waveplate with a periodic silver film 2 × 2 rectangular hole array with a thickness less than λ/50. Numerical simulation shows that the waveplate can efficiently transform a circular polarized wave into a linearly polarized one at the center of 1550 nm, and its bandwidth is 525 nm. Furthermore, the quarter waveplate can efficiently invert linear polarization into circular polarization at 1550 nm, which ellipticity is near unit. With an array of small holes on a metal film to enhance transmission, this structure can increase the transmission to 0.44. The broadband quarter waveplate can be used in communication system and near infrared band system, and be integrated with other optical devices at nanoscale to achieve polarization operation, detection, and sensing.