A single-walled carbon nanotube (SWCNT) has the shape of rolled-up graphene and right- or left-handed structures depending on the way it is rolled-up. Circular dichroism (CD) spectra have been observed using SWCNT with a structure that is rolled-up in a particular way [1]. On the other hand, the evanescent field of an optical nanofiber (ONF) is known to be elliptically-polarized (EPL) with polarization direction locked to the propagation direction of light within the fiber [2]. In previous work, optical isolators were realized using EPL and cold atoms with in states which exhibited large CD [3]. We propose that a similar non-reciprocal optical effect could allow the creation of optical isolators at room temperature using SWCNTs of a given chirality coupled to the evanescent field of a nanofiber [4]. In this study, we will explore the principle of such a device and proposals for improving its performance.

Figure 1 shows a conceptual diagram of the device. SWCNT was deposited on the ONF as depicted in Fig. 1. By rotating the linear-polarized light (LPL) passing into the ONF, the mode’s evanescent field intensity distribution rotates around the ONF axis. The transmittance was minimized when the EPL coincided with the position where the SWCNTs were attached in the left hand system. On the other hand, the transmittance did not change in the corresponding right hand system. In the presentation, we will present the results of research on the performance evaluation of this non-reciprocal optical system and discuss the interaction between CD of SWCNT and EPL.