Photonic slide rule: Simultaneous resolving of wavelength and polarization state


Figure 1. (a) The conventional slide rule (left) is driven by mechanical rotation and read out visually with an easy-to-use size. As an analog, an ultra-compact prototype of the photonic counterpart (right) based on the metasurface platform is shown. The metadevice is designed with the incident frequency and polarization state function with varying phases. Correspondingly, angle-resolved interfered spots are observed in the far-field. (b) The metadevice design can be decoupled to two parts: vortex generation and achromatic annular focusing. Both phase profiles are dependent on the frequency. In the vortex beam design, the phases rotate in opposite directions and at distinct angular velocities with different topological charges. (c) The interference holography generates a moving symmetric annulus with intensity distribution indicated as the purple curve on the right. As a representative, intensity distribution at wavelength 3.75 μm is for demonstration. (d) The captured images at different frequencies on the same focal plane with left circular light incidence. The annular intensity distribution rotates with the incident frequency. Credit: Feilong Yu, Jin Chen, Lujun Huang, Zengyue Zhao, Jiuxu Wang, Rong Jin, Jian Chen, Jian Wang, Andrey E Miroshnichenko, Tianxin Li, Guanhai Li, Xiaoshuang Chen and Wei Lu

Mid-wavelength infrared (MWIR) is a unique regime with various potential applications in fingerprint detections. It is also one of three atmospheric transmission windows that shows significant possibilities in low-light-level night vision and free-space communications. The accurate detection of unknown photons in this band plays an indispensable role in aeronautics and astronautics applications. However, with the conventional bulky measurement setup with many cascaded optical elements or metasurface based devices, they are limited by the restricted longitudinal dispersion and the lack of simultaneous resolving of wavelength and polarization state.

In a new paper published in Light: Science & Applications, a team of scientists, led by Dr. Guanhai Li from the state key laboratory of infrared physics, Shanghai Institute of Technical Physics, China, and co-workers have proposed a versatile photonic slide rule based on an all-silicon metasurface that enables the simultaneous reconstruction of incident ‘ frequency and polarization state. The metasurface leverages both achromatically focusing and azimuthally evolving phases with topological charges +1 and -1 to ensure the confocal annular intensity distributions in the far-field.

Inspired by conventional slide rules, which embed the computation rules into the inherent evolutions of physical parameters, the team presents the photonic slide rule and demonstrate the prototype to characterize incident photons’ frequency and polarization state. With an all-silicon metasurface design, different wavelengths and polarization states correspond to different phase profiles, thus resulting in the angle-resolved focusing spots in the far-field. Two distinct groups of meta-atoms are designed to have different vortex beam carriers and phase dispersions. The angle-resolved interference pattern in the far-field of two groups of meta-atoms provides an easy-to-access retrieval of the wavelength and the state of polarization. As an analog, they successfully migrate the arithmetic logic of dispersive phases to the inherent variation of photonic dimensions-frequency and polarization with the all-silicon metasurface.

Photonic slide rule:Simultaneous resolving of wavelength and polarization state
Figure 2. The captured images on the focal plane at different frequencies under left and right circular polarization incidence. The inner and outer rings are respectively lightened as a function of the incident polarization state. Credit: Feilong Yu, Jin Chen, Lujun Huang, Zengyue Zhao, Jiuxu Wang, Rong Jin, Jian Chen, Jian Wang, Andrey E Miroshnichenko, Tianxin Li, Guanhai Li, Xiaoshuang Chen and Wei Lu

The research team selected the meta-atoms with different polarization responses and arranged with spatial multiplexing to further construct the secondary mapping of the unknown photon polarization information in the focal plane. With this handling, they achieved the simultaneous resolving of the frequency and polarization state of the unknown incident photon. As shown in Figure 2, the rotation angles of the inner and outer rings resolve the frequency of the incident photon, while the polarization information of the incident photon can be straightforwardly obtained from the position of the focusing spots. The inner ring corresponds to the left-handed circular polarization state, and the outer ring is right-handed circular polarization state.

Finally, through theoretical analysis, numerical simulation and experimental measurement, the research team confirmed that the metasurface-based photonic slide rule can effectively overcome the limitation of traditional bulk material devices in the workspace, especially the axial distance, and realized a new scheme of ultra-compact and highly-integrated characterization of the unknown photons’ wavelength and polarization state. This work provides an analog of the conventional slide rule to flexibly characterize the photons in an ultra-compact and multifunctional way and may find applications in integrated optical circuits or pocketable devices.

Dr. Yu Feilong and Dr. Chen Jin are the co-first authors of this paper, and Dr. Li Guanhai is the corresponding author. Profs. Chen Xiaoshuang and Lu Wei provided significant instructions on this work.

Cylindrical vector beam multiplexer/demultiplexer using off-axis polarization control

More information:
Feilong Yu et al, Photonic slide rule with metasurfaces, Light: Science & Applications (2022). DOI: 10.1038/s41377-022-00765-0

Photonic slide rule: Simultaneous resolving of wavelength and polarization state (2022, May 2)
retrieved 2 May 2022

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