Ultra-High and Near-Zero Refractive Indices of Magnetron Sputtered Thin-Film Metamaterials Based on Ti_xO_y

Table 2

The band gap energies of samples and the corresponding wavelengths.

Sample	Direct transition		Indirect transition
	, eV	λ range, nm	, eV	range, nm
1	1.05	729–960	1.10	945–1050
	1.97	530–588	2.05	563–590
	3.00	386–400	3.00	382–405
	3.71	318–326	3.57	318–326
2	0.85	867–1087	0.97	1127–1228
	1.73	650–688	1.78	650–688
	2.61	427–460	2.57	457–478
	3.08	386–400	3.09	387–401
	3.56	272–336	3.43	317–336
3	2.68	387–406	1.19	652–775
	3.21	344–366	1.77	471–516
	3.33	274–322	2.75	392–413
	4.39	258–263	3.17	352–365