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An optical fiber immunosensor with a low detection limit based on plasmon coupling enhancement is proposed for detecting human immunoglobulin G (IgG). Graphene oxide (GO)-gold nanorod composites are synthesized and modified onto a photonic crystal fiber (PCF) surface coated with a Au film. GO, as a biosensitive layer, is used to decorate the gold nanorods and concentrate target molecules. The experimental result indicates that the refractive index sensitivity is drastically enhanced to 22248 nm/RIU because of plasmon coupling. Correspondingly, the human IgG detection limit decreases to 6 ng/mL. Moreover, the PCF is insensitive to temperature fluctuation, which can further reduce the measurement error.

A sapphire fiber high temperature sensor based on Fabry-Perot interference was studied in the paper. A sapphire wafer served as the Fabry-Perot cavity was fixed to the end face of the sapphire fiber. The sensor was encapsulated in an alumina ceramic tube-ceramic sleeve structure to improve structural stability. Experiment results showed the sensor had a wide temperature measurement range of 25 °C–1550 °C. The temperature sensitivity reached 32.5 pm/°C at 1550 °C. Furthermore, the temperature was demodulated from the interference spectrum through fast Fourier transform algorithm. It was concluded that the sapphire fiber sensor with advantages of small size, good stability and a wide range of temperature measurement is very promising for measuring high temperature.

Mars surface composition detector (MarSCoDe) is a scientific instrument suite onboard the Mars rover of the “Tianwen-1” mission, which uses laser-induced breakdown spectroscopy and shortwave infrared spectroscopy to detect the composition of soils and rocks at the surface of Mars. The optical head unit (OHU) is the core hardware of MarSCoDe, containing a Cassegrain telescope and other optical modules for lasers generation and signals transmission. The unit lacks thermal control resources and is located outside the rover’s cabin, which will directly face the Martian surface drastic temperature changes. We introduce the optomechanical designs that realize the lightweight and high thermal stability of the OHU optical system, especially the designs and implementations of the semiopen primary mirror based on silicon carbide and the fully closed optical bench based on carbon fiber-reinforced polymer. Meanwhile, the advantages and difficulties of silicon carbide, long carbon fiber-reinforced silicon carbide composites, and carbon fiber-reinforced polymer materials used for small and compact optomechanical systems are discussed. Subsequently, the environmental adaptability of the telescope system of OHU was studied through analytical and experimental methods, which show that it can achieve the required optical performance over a temperature range of approximately 100°C.

Mars Surface Composition Detector (MarSCoDe) is a scientific payload onboard the Mars rover of China’s Tianwen-1 mission. With the capability of 1.6∼7 m remote detection and analysis, MarSCoDe instrument suite consists of a two dimensional pointing mirror and an optical head outside the rover cabin, a Laser Induced Breakdown Spectroscopy (LIBS) spectrometer and a Short Wave Infrared (SWIR) spectrometer collectively covering 240∼2400 nm and a master controller unit inside the rover body, calibration target sets, optical fibers and power cables connecting the internal and external units. Combining the techniques of active LIBS, passive SWIR and micro-imaging, MarSCoDe provides functions including elemental composition discrimination and quantitative determination, classification of rock and soil characteristics, sample texture imaging and characterization of plasma-excited area. This paper introduces MarSCoDe mainly in terms of scientific objectives, design requirements, assembly and implementation, spectral and radiation calibration, and performance verification. The LIBS laser irradiance on the target can soundly exceed 10 MW/mm2, and the performance of the LIBS module operated at different temperatures has been tested. The field of view of the SWIR spectrometer is 36.5 mrad. The micro-imager can extract the central pixel area of 320 × 320 and 1024 × 1024, and the former is binned into 64 × 64. The 2D pointing mirror has a wide forward detection range and a narrow backward calibration range, with the pointing pitch accuracy better than 0.133°.

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Additional file 2: Table S1

Additional file 1: Figure S1

A review is presented on high temperature measurement technology based on sapphire optical fiber. This review paper focuses on the sensing theory, sensor structures and sensing performances of different sapphire fiber sensors. Firstly, there is discussion on pyrometer made from sapphire fiber and description on its corresponding sensing properties. Secondly, there are summary on sapphire fiber Bragg grating (SFBG) inscribed by different methods for high temperature measurement. Thirdly, there are analysis on sapphire fiber sensors based on Fabry Perot (FP) interference with different structures. All above, subsequently, lead to the discussion on microwave interferometry and Raman scattering-based sapphire fiber sensors. Then a sensing performance comparison of sapphire pyrometers based on different detection principles are discussed. On the premise of all above, a future prospect and development trend of high-temperature sapphire fiber sensor are addressed as well.