Focusing of in-plane hyperbolic polaritons in van der waals crystals with tailored infrared nanoantennas

J.M.-S. acknowledges financial support from the Ramón y Cajal Program of the Government of Spain and FSE (RYC2018-026196-I) and the Spanish Ministry of Science and Innovation (State Plan for Scientific and Technical Research and Innovation grant number PID2019-110308GA-I00). P.A.-G. acknowledges support from the European Research Council under starting grant no. 715496, 2DNANOPTICA, and the Spanish Ministry of Science and Innovation (State Plan for Scientific and Technical Research and Innovation grant number PID2019-111156GB-I00). J.T.-G. acknowledges support through the Severo Ochoa Program from the Government of the Principality of Asturias (PA-18-PF-BP17-126). G.A.-P. acknowledges support through the Severo Ochoa Program from the Government of the Principality of Asturias (PA-20-PF-BP19-053). K.V.V. and V.S.V. acknowledge the financial support from the Ministry of Science and Higher Education of the Russian Federation (agreement no. 075-15-2021-606). A.Y.N. acknowledges the Spanish Ministry of Science, Innovation, and Universities (national projects MAT2017-88358-C3-3-R and PID2020-115221GB-C42) and the Basque Department of Education (PIBA-2020-1-0014). R.H. acknowledges financial support from the Spanish Ministry of Science, Innovation, and Universities (national project number RTI2018-094830-B-100 and project number MDM-2016-0618 of the Marie de Maeztu Units of Excellence Program) and the Basque Government (grant number IT1164-19).