Fig. 1. Micrographs of columnar microholes. (a) Side view of single hole; (b) top view of single hole; (c) side view of two holes; (d) top view of two holes

Fig. 2. Schematic diagram of sensor optical path

Fig. 3. Reflection spectra of sensor. (a) L=70, 80, 90 μm; (b) L=80 μm

Fig. 4. Fourier frequency spectra of sensor

Fig. 5. Transmission spectra of sensor under change of refractive index

Fig. 6. Transmission spectral intensity of sensor under different refractive indices

Fig. 7. Schematic diagram of cryogenic device

Fig. 8. Spectra of sensor under temperature change

Fig. 9. Linear fitting at dip1 for cryogenic experiment

Fig. 10. Spectra of sensor under humidity change

Fig. 11. Linear fitting of humidity experiment at dip1

Fig. 12. Schematic diagram of refractive index device

Fig. 13. Spectra of sensor under refractive index change

Fig. 14. Linear fitting of refractive index experiment at dip1

Fig. 15. Schematic diagram of high temperature device

Fig. 16. Spectra of sensor under temperature change

Fig. 17. Linear fitting of high temperature experimental results at dip1

Fig. 18. Schematic diagram of gas pressure device

Fig. 19. Spectra of sensor under gas pressure change

Fig. 20. Linear fitting of gas pressure experimental results at dip1