Fig. 1. Structural diagrams of two kinds of photonic-plasmonic hybrid microcavities. (a) Bowtie plasmonic nanoantenna is placed horizontally; (b) bowtie plasmonic nanoantenna is placed vertically; (c) enlarged diagram of the bowtie plasmonic nanoantenna

Fig. 2. Electric field intensity distribution of two photonic-plasmonic hybrid microcavities. (a)-(c) Electric field intensity distribution of XY, XZ, and YZ cross sections when the bowtie plasmonic nanoantenna is placed horizontally; (d)-(f) electric field intensity distribution of XY, XZ, and YZ cross sections when the bowtie plasmonic nanoantenna is placed vertically

Fig. 3. Optical properties of the two hybrid microcavities as functions of the gap of the bowtie plasmonic nanoantenna. (a) Quality factor Q; (b) effective mode volume V; (c) figure of merit Q/V

Fig. 4. Optical properties of the two hybrid microcavities as functions of the angle of the bowtie plasmonic nanoantenna. (a) Quality factor Q; (b) effective mode volume V; (c) figure of merit Q/V

Fig. 5. Optical properties of the two hybrid microcavities as functions of the length of the bowtie plasmonic nanoantenna. (a) Quality factor Q; (b) effective mode volume V; (c) figure of merit Q/V

Fig. 6. Optical properties of the two hybrid microcavities as functions of the thickness of the bowtie plasmonic nanoantenna. (a) Quality factor Q; (b) effective mode volume V; (c) figure of merit Q/V

Fig. 7. Optical properties of the two hybrid microcavities as functions of the location of the bowtie plasmonic nanoantenna along X direction. (a) Quality factor Q; (b) effective mode volume V; (c) figure of merit Q/V