Contents I. Introduction
Rapid advances in semiconductor industry complementary metal–oxide–semiconductor (CMOS) fabrication process have enabled the integration of a camera onto a single silicon chip. Referred to as CMOS image sensor, a camera-on-a-chip offers significant advantages in terms of system miniaturization and manufacturing cost [1]. As a result, CMOS image sensors can now be found in a wide range of consumer electronic products from mobile phones, PC mouse, and webcam to fax machines, to name a few. Like the vast majority of commercially available camera systems, CMOS image sensors are essentially designed to image the world in terms of intensity and color. To capture the third characteristic of light that is polarization, Kalayjian et al. proposed to integrate a micropolarizer array on top of the image sensor [2]. A number of implementations have subsequently been proposed [3]–[5]. In each case, selective etching was required to pattern the micropolarizer at the pixel pitch [2]–[5]. In this letter, we propose a novel micropolarizer array fabrication technology that removes the need for selective etching, which is a difficult process to control at the micrometer scale [5]. Instead, we propose to use the well-controlled-process of ultraviolet (UV) photolithography to enable the patterning of a high resolution pixel-level micropolarizer array layer with submicron thickness. We describe this novel micropolarizer fabrication technology in Section II. We report and discuss experimental results in Section III. Finally, a conclusion is drawn in Section IV.
