Error correction for Mueller matrix ellipsometry based on a reference optical path.

To reduce the error induced by light source fluctuations, motor rotation instability, environment, and other factors in real-time measurements using dual-rotating compensator Mueller matrix ellipsometry (DRC-MME), an error-correction method based on a reference optical path is proposed. A modified Mueller matrix expression was derived theoretically by introducing the reference optical path of the DRC-MME system. Simulation analysis and experimental verification of the air, polarizer, and S i O 2 samples were performed using this method. The absolute error of the Mueller matrix elements of the S i O 2 samples decreased from less than 0.028 to less than 0.008, and the standard deviation decreased from 0.9% to 0.3%. This method has certain guiding significance in improving the measurement accuracy of DRC-MME.

Correction: Yan, L., et al. A Micro Bubble Structure Based Fabry⁻Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost Characteristics Sensors, 2017, 17, 555.

An correction is presented to correct Figure 5a in [Sensors, 2017, 17, 555].

A High-Sensitive Pressure Sensor Using a Single-Mode Fiber Embedded Microbubble with Thin Film Characteristics.

A new fiber pressure sensor is proposed and analyzed in this paper. A commercial arc fusion splicer and pressure-assisted arc discharge technology are used here to fabricate a silica hollow microbubble from a common glass tube with the characteristics of a thin film. Then the single mode fiber is embedded into the microbubble to form a fiber Fabry-Perot interferometer by measuring the reflected interference spectrum from the fiber tip and microbubble end. As the wall thickness of the micro-bubble can reach up to several micrometers, it can then be used for measuring the outer pressure with high sensitivity. The fabrication method has the merits of being simple, low in cost, and is easy to control. Experimental results show that its pressure sensitivity can reach 164.56 pm/kPa and the temperature sensitivity can reach 4 pm/°C. Therefore, it also has the advantage of being insensitive to temperature fluctuation.

A Micro Bubble Structure Based Fabry-Perot Optical Fiber Strain Sensor with High Sensitivity and Low-Cost Characteristics.

A high-sensitivity, low-cost, ultrathin, hollow fiber micro bubble structure was proposed; such a bubble can be used to develop a high-sensitivity strain sensor based on a Fabry-Perot interferometer (FPI). The micro bubble is fabricated at the fiber tip by splicing a glass tube to a single mode fiber (SMF) and then the glass tube is filled with gas in order to expand and form a micro bubble. The sensitivity of the strain sensor with a cavity length of about 155 µm and a bubble wall thickness of about 6 µm was measured to be up to 8.14 pm/µÏµ.