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28LMI-I-16
Prospects for the application of vortex beams of mid- and far-infrared ranges in surface plasmonics
B. Knyazev1, Y. Choporova1, O. Kameshkov2, A. Nikitin3, N. Osintseva1, V. Pavelyev4 1Budker Instutute of Nuclear Physics SB RAS, Free Electron Laser, Novosibirsk, Russian Federation
2Novosibirsk State University, Physics, Novosibirsk, Russian Federation
3Scientific and Technology Center of Unique Instrumentation, Terahertz Laboratoty, Moscow,
Russian Federation
4Samara University, Nanotechnology, Samara, Russian Federation
Photonics and plasmonics are the most rapidly developing areas of modern optics. The current state and prospects of further development of these areas of science are vividly described in articles [1] and [2]. Surface plasmon polaritons, electromagnetic waves coupled to conductive surfaces, and vector and vortex beams of light are objects studied in plasmonics and photonics. They are used in many applications such as surface sensing and processing, communication systems, and so on. In a number of works (see, e. g. [3]), vortex beams illuminated a system of spiral slots in thin metal films to form radially converging surface plasmons carrying orbital angular momentum. In several papers (see, e. g., [4]), the propagation of rotating plasmons along cylinders with a screw thread has been demonstrated. Although such plasmons can be called vortex plasmons, the sign and magnitude of their topological charge are determined by the geometry of the conductor and cannot be changed. Cylindrical waveguides, along which a superposition of plasmons with different orbital moments is transmitted, can be used in different material applications, as well as in multiplex communication lines in photonic devices. Since the path length of plasmons in the visible range are only tens of microns, it is beneficial to use plasmons of mid- and far-infrared ranges. To implement such systems in these ranges, it is necessary to have an appropriate radiation source, create a system for launching surface plasmons, study the propagation characteristics of vortex plasmons, and create mixers and sorters for multimode beams. In this paper, we report the results of numerical and experimental studies of several variants of devices for the formation, transportation and investigation of vortex plasmon polaritons at wavelengths of 140, 47 and 8.5 micrometers, using the Novosibirsk free electron laser and the quantum cascade laser as radiation sources. To launch plasmons by end-fire-coupling technique or using diffraction elements, Gaussian and Bessel beams of different orders are used [5-9].
This work was supported in parts by RSF grants 19-12-00103 and 19-72-20202. The experiments were carried out at the unique facility "Novosibirsk free electron laser" using the equipment of the Siberian Center of Synchrotron and Terahertz Radiation.
References
[1] H. Rubinsztein-Dunlop, et al. Roadmap on structured light, J. Opt., V. 19, 013001 (2017).
[2] M. I. Stockman, et al. Roadmap on plasmonics, J. Opt., V. 20, 043001 (2018).
[3] Seung-Yeol Lee, et al. Controlling the state of surface plasmon vortex by changing the topological charge and polarization state, Proc. SPIE, V. 7757, 77573G (2010).
[4] H.-Z. Yao, S. Zhong, Wideband circularly polarized vortex surface modes on helically grooved metal wires, IEEE Photonics J., V. 7, 4600707 (2015).
[5] B. A. Knyazev, Y. Y. Choporova, M. S. Mitkov, V. S. Pavelyev, B. O. Volodkin, Generation of terahertz surface plasmon polaritons using nondiffractive Bessel beams with orbital angular momentum. Phys. Rev. Lett., V. 115, 163901 (2015).
[6] Y. Y. Choporova, B. A. Knyazev, G. N. Kulipanov, et al., High-power Bessel beams with orbital angular momentum in the terahertz range. Phys. Rev. A, V. 96, 023846 (2017). [7] B. Knyazev, V. Serbo, Beams of photons with a nonzero projection of the orbital angular momentum - new results, Phys. Usp., V. 61, 449 (2018).
[8] V. S. Pavelyev, B. O. Volodkin, K. N. Tukmakov, B. A. Knyazev, Yu. Yu. Choporova, Transmissive diffractive micro-optics for high-power THz laser radiation. In AIP Conf. Proc., V. 1989, No. 1, p. 020025 (2018).
[9] B. A. Knyazev, V. V. Gerasimov, A. K. Nikitin, I. A. Azarov, Yu. Yu. Choporova, Propagation of terahertz surface plasmon polaritons around a convex metal-dielectric interface, JOSA B, v. 36, 1684 (2019).
