Harbin Institute of Technology
Publishes on Advanced Fiber Optic Sensors, Photonic and Optical Devices, Advanced Fiber Laser Technologies. 4 papers and 133 citations.
Add your photo, update your bio, and get notified when your ranking changes.
The spectral response of the dual resonant peaks of a 100 µm period fibre grating to surrounding refractive index (SRI) from n = 1 to 1.74 has been investigated. The two peaks were found to shift in opposite directions over –180 and +300 nm, respectively, as the SRI changed. A novel chemical sensing scheme with enhanced sensitivity based on the measurement of the separation of the two peaks instead of a shift in a single peak is also presented.
It is found that the coupling of the guided core mode to a higher order cladding mode may lead to dual resonant wavelengths in long-period gratings (LPGs). The dual peaks of the LP015 cladding mode have been observed to shift towards each other during the second exposure of a 100 µm period grating. It is also shown that the resonant wavelengths of LPGs can be tuned over a wide range by the post-exposure technique.
Effects of photoperiod and temperature on diapause induction and termination were investigated in both aestival and hibernal pupae of Pegomyia bicolor Wiedemann under field and laboratory conditions. In the field, summer diapause had occurred already in part of the first pupal population; the proportion of diapause gradually rose as the day length and temperature increased. This fly is a short‐day species with a pupal summer and winter diapause. Summer diapause was induced by both long day‐lengths and mild temperatures. The whole larval life is sensitive to photoperiod. Winter diapause was induced mainly by low temperatures, especially in the first 10 days after pupation. High temperatures strongly enhanced summer diapause induction regardless of photoperiod. The diapause‐averting influence of short photoperiods was fully expressed only at moderately low temperatures. High temperatures delayed diapause development, resulting in a rather long summer diapause; whereas low temperatures hastened it, leading to a short winter diapause and showing a low thermal threshold for diapause development. In the field, the post‐diapause development started in January, the coldest month, suggesting that the thermal requirements for post‐diapause development is also low.