Fig. 4

Performance improvement strategies for guided-wave nanophotonic biochemical sensors. a TM mode and thinner waveguide. Mechanisms indicated by the simulated electric field intensity distributions of (i) TE mode in 220 nm × 500 nm waveguide; (ii) TM mode in 220 nm × 500 nm waveguide; (iii) TE mode in 90 nm × 800 nm waveguide. b Suspended waveguide. Example using suspended MRR (Reproduced with permission from [74]). c Slot waveguide: (i) lateral slot (Reproduced with permission from [79]); (ii) horizontal slot (Reproduced with permission from [87]). d (i) Subwavelength grating waveguide (Reproduced with permission from [90]); (ii) Subwavelength multibox waveguide (Reproduced with permission from [92]). e Slow light effect: (i) schematic illustration of slow light enhancement mechanism (Reproduced with permission from [94]); (ii) slow light enhanced sensitivity in Ln PhC microcavity side coupled to W1 PhC waveguide (Reproduced with permission from [103]); (iii) absorption enhancement in PhC slot waveguide (Reproduced with permission from [110]). e Vernier light effect. Schematic illustration of sensor configuration employing Vernier effect and typical Vernier spectra in RI sensing