@article {1309426,
	title = {Experimental Realization of an Epsilon-Near-Zero Graded-Index Metalens at Terahertz Frequencies},
	journal = {Physical Review Applied},
	volume = {8},
	number = {034036},
	year = {2017},
	url = {https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.8.034036},
	author = {Victor Pacheco-Pe{\~n}a and Nader Engheta and Sergei Kuznetsov and Alexander Gentselev and Miguel Beruete}
}
