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We synthesized bicolor Mn-doped CuInS2 (CIS)/ZnS core/shell nanocrystals (NCs), in which Mn2+ ions and the CIS core were separated with a ZnS layer, and both Mn2+ ions and CIS cores could emit simultaneously. Transmission electron microscopy and powder X-ray diffraction measurements indicated the epitaxial growth of ZnS shell on the CuInS2 core, and electron paramagnetic resonance spectrum indicated that Mn2+ ions were on the lattice points of ZnS shell. By integrating these bicolor NCs with commercial InGaN-based blue-emitting diodes, tricolor white light-emitting diodes with color rendering index of 83 were obtained.

High color-purity CdZnSeS alloy cores and CdZnSeS/ZnS core/shell quantum dots (QDs) with 3, 11 and 17 monolayer (ML) ZnS shells are synthesized, and the narrow emission (full-width at half-maximum: ∼21 nm) is ascribed to the high size uniformity of QDs and the narrow linewidth of single QD spectra. Ultraviolet (UV) irradiation experiments show that the photo-stabilities of the samples improve remarkably with increasing shell thickness, but the photo-stability clearly decreases when the shell thickness is further increased to 17 MLs. Spectroelectrochemical (SEC) measurements indicate that the exciton recombination of QDs is mainly affected by surface electronic traps, and the interaction between exciton recombination centers and surface traps is significantly weakened with the increase in shell thickness due to the decreased wave function overlap of the exciton and surface traps. In the case of the 17 ML shell, the reduced photo-stability is due to increased interfacial defects caused by stress release during UV illumination, which can be proved by high-resolution transmission electron microscopy images and X-ray diffraction patterns. Furthermore, based on QDs' theoretical mass calculations, a photo-stable white light-emitting diode is fabricated by encapsulating with a thick-shell QD, and an exceptional color gamut of 130% relative to the National Television Systems Committee color space can be achieved. Also, its colorimetry and photometry are discussed in detail.

We investigate to generate coherent and frequency-lock optical multi-carriers by using cascaded phase modulators and recirculating frequency shifter (RFS) based on an EDFA loop. The phase and amplitude relation of RF signals on two cascaded phase modulators and the impact of EDFA gain are investigated. Experimental results are in good agreement with the theoretical analysis. The performance of 113 coherent and frequency-lock subcarriers with tone-to-noise ratio larger than 26dB and amplitude difference of 5dB obtained after a tilt filter covering totally 22.6nm shows that this scheme is a promising technique for the coming Tb/s optical communication.

We proposed and experimentally demonstrated a highly sensitive optical fiber torsion sensor based on a reflective Lyot filter for the first time to our knowledge. The reflective Lyot filter is constructed by inserting a section of polarization-maintaining fiber (PMF) between a fiber linear polarizer and a 3dB coupler based fiber loop reflector. Based on the intensity modulation, the proposed torsion sensor exhibits a high torsion sensitivity of up to 20.336 dB/rad, one order of magnitude higher than the achieved in state-of-the-art. In contrast, the temperature cross-sensitivity and strain cross-sensitivity of the proposed torsion sensor are low to -2.0 × 10^-4 rad/°C and -6.39 × 10^-6 rad/με, respectively, thus overcoming the cross-sensitivity problem resulting from temperature and strain. Moreover, we perform the theoretical simulation of the proposed torsion sensor, and the simulation result obtained agrees well with the experiment results, vividly confirming the viability of the fiber Lyot filter based torsion sensor. Such fiber Lyot filter may find potential applications of highly sensitive torsion sensors in the field of modern smart structure monitoring.