1. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. (a) Schematic of the proposed Fabry–Pérot (FP) cavity with curved surfaces. The cylindrical Bragg mirrors allow light confinement in the lateral direction while the capillary tube with the fluid inside acting as a cylindrical lens in the vertical direction. Due to this confinement, high-quality factors (Q) in the order of 1000 could be achieved. A set of optical fibers is used to inject light into the cavity and collect and deliver it to the power meter. (b) Simplified fabrication sequence of the volume refractometer: (i) patterning of single crystal silicon wafer with thermal oxide, (ii) transfer into silicon by deep reactive ion etching (DRIE), (iii) assembly of the microcapillary tube, (iv) positioning of input–output optical fibers and filling the capillary with the liquid analyte. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

2. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. Photo of the setup illustrating the silicon chip with the capillary tube connected to the injection tubing, and the input/output fibers on their positioners. The inset is a zoom of the different cavities, also indicating the placement of the fiber pair, one being used for light injection and the other for recording the spectral transmission response. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

3. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. (a) Schematic indicates the new measurement criterion of the power level at a fixed wavelength in dBm/RIU. (b) Schematic indicates the linear region when the sensing signal is converted to the refractive index unit. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

4. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. Schematic indicates the trade-off between the sensitivity and range for different Q. The high Q factors offer high sensitivity but limited range, and vice versa for the low Q. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

5. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. The spectra of different mixture ratios between acetone and deionized water measured by the refractometer consisting of a cylindrical FP cavity with a microtube inside. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

6. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. The normalized spectra of different mixture ratios between acetone and deionized water measured by the refractometer consisting of a cylindrical FP cavity with the microtube inside. The blue dashed line represents a reference for detecting the power level change linked to the refractive index. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

7. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. The shift in the normalized power at the reference line with the change of the analyte refractive index. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501

8. Date of download: 7/11/2016 Copyright © 2016 SPIE. All rights reserved. The shift in the wavelength of the peak with the change of the analyte refractive index. Figure Legend: From: Volume refractometry of liquids using stable optofluidic Fabry–Pérot resonator with curved surfaces J. Micro/Nanolith. MEMS MOEMS. 2015;14(4):045501. doi:10.1117/1.JMM.14.4.045501