Table 2. Comparison of the sensing performance of the proposed wrinkled graphene structure with recently published refractive index sensors in the mid-infrared region.

Recently published refractive index sensors	Resonant wavelength (µm)	Max sensitivity (nm RIU−1)	Max FOM (RIU−1)
Multimode interference in tellurite no-core optical fibers (2023)40	4–5	3069.1	22
Implanted cavities in metal–insulator–metal (MIM) waveguide (2019)41	2.75	2602.5	13
Resonant toroidal plasmonic metasensor (2019)42	5.5	2500	4
Metal–insulator–metal waveguide-based square-ring resonator plasmonic refractive index sensor (2024)43	3.6	2700	8.1
Fano-resonance plasmonic nanosensor based on a tapered waveguide cavity resonator (2024)44	2.52	2544.3	40.54
Silicon-on-insulator ring resonator plasmonic sensor based on graphene and gold nano-discs (2024)45	1.645	730	56.15
Hybrid plasmonic sensor based on graphene and an array of asymmetric gold nano-antennas (2019)46	7.2	2300	28.75
Graphene-decorated grating on a high dielectric substrate (2019)47	5.5	2780	17
Graphene-based diffractive grating structure (2017)48	9.5	2000	14.2
Dual-band graphene metamaterials (2019)49	7.85	2880	12.9
Wrinkled graphene structures on SiO 2 nanospheres with a close-packed curvature pattern (this study)	5.5	3250	63.2