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A method for video-rate display with optimized single UCNP brightness by integrating the full emission intensity over excitation time and lifetime.

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We have investigated photoinduced infrared absorption in p-doped Si/SiGe quantum wells. The absorption spectra exhibit two distinct features: free-carrier absorption and intersubband absorption in the valence band. The photoinduced absorption in both p and s polarizations is found to depend on the carrier density and strongly differs from the original absorption of the doped quantum wells. Photoinduced intersubband absorption is attributed to carriers away from the Brillouin zone center. We show that photoinduced intersubband absorption spectroscopy can provide useful information on valence band mixing effects in Si/SiGe quantum wells.

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We proposed a differential fiber-optic SPR remote sensor with ultra-high sensitivity in telecom band. The working band of the sensor is designed as the C-band which is the low loss band of optical fiber communication aiming to improve the sensitivity and enable the capability of remote monitoring. The sensor head is a BK7 prism coated with Au/TiO2 films, enabling two channels for differential intensity interrogation. The intensities of the reflected lights through the channels vary oppositely within the measurement range of refractive index. Due to the sharp dip of angular resonant response in the C-band, the differential signal produces a steep slope as the refractive index of the sample varies, thus higher sensitivity is expected in a narrow measurement range. According to the results, the sensitivity is as high as 456 V/RIUs within the narrow measurement range of 1.3×10−2 RIUs and the resolution reaches to 6×10−6 RIUs. The measurement range can be tuned conveniently by adjusting the thickness of TiO2 film and can be expanded by increasing the number of sensing channels, which provides great convenience for the application of biosensor requiring high sensitivity.

Fiber-optic surface plasmon resonance (SPR) sensors possess the advantages of small size, flexible, allowing for a smaller sample volume, easy to be integrated, and high sensitivity. They have been intensively developed in recent decades. However, the polarizing nature of the surface plasmon waves (SPWs) always hinders the acquisition of SPR spectrum with high signal-noise ratio in wavelength modulation unless a polarizer is employed. The addition of polarizer complicates the system and reduces the degree of compactness. In this work, we propose and demonstrate a novel, polarization-independent fiber-optic SPR sensor based on a BK7 bi-prism with two incident planes orthogonal to each other. In the bi-prism, TM-polarized components of non-polarized incident lights excite SPWs on the first sensing channel, meanwhile the TE components and the remaining TM components are reflected, then the reflected TE components serve as TM components of incident lights for the second sensing channel to excite SPWs. Simulations show the proposed SPR structure permit us to completely eliminate the polarization dependence of the plasmon excitation. Experimental results agree well with the simulations. This kind of devices can be considered an excellent option for development of simple and compact SPR chemical sensors.