We experimentally demonstrate for the first time to our knowledge electrically injected vertical-cavity surfaceemitting lasers(VCSELs) with post-supported high-contrast gratings(HCGs) at 940 nm. The HCG-VCSELs have tw...We experimentally demonstrate for the first time to our knowledge electrically injected vertical-cavity surfaceemitting lasers(VCSELs) with post-supported high-contrast gratings(HCGs) at 940 nm. The HCG-VCSELs have two posts to support the air-suspended HCGs, which are realized by simple fabrication without critical point drying. The HCG-VCSEL achieves a threshold current of about 0.65 m A and a side-mode suppression ratio of 43.6 d B under continuous-wave operation at 25℃. Theoretically the HCG-VCSEL with a λ∕2-cavity for the transverse magnetic polarization has a smaller effective mode length of 1.38 ·(λ∕n). Thus, the relaxation resonance frequency can be increased by 16% compared with that of the conventional VCSEL. The modulation speed of 100 Gbit/s for the HCG-VCSEL is expected in the on–off keying modulation format. Our easy design of HCGVCSELs has great potential for applications in optical interconnects, sensing, illumination, and so on.展开更多
Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters（Au NCs） protected by 11-mercaptoundecanoic acid（11-MUA）,which have e...Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters（Au NCs） protected by 11-mercaptoundecanoic acid（11-MUA）,which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions（Cu^（2＋）） and iron ions（Fe^（3＋）） in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe^（3＋） was 0.8-4.5 mmol/L（R^2= 0.992） and 4.5-11.0 mmol/L（R^2= 0.997）.And Cu^（2＋） has a lower linear range（0.1-1.0 mmol/L,R2= 0.993）.When EDTA was added into the reaction system,it was observed that the quenching effect of Cu^（2＋） and Fe^（3＋）on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu（2＋） was achieved by EDTA masking of Fe^（3＋）.In addition,we realized the metal ions detection application of Au NCs in the serum展开更多
基金National Natural Science Foundation of China(62075209,61675193)Beijing Natural Science Foundation(Z200006).
文摘We experimentally demonstrate for the first time to our knowledge electrically injected vertical-cavity surfaceemitting lasers(VCSELs) with post-supported high-contrast gratings(HCGs) at 940 nm. The HCG-VCSELs have two posts to support the air-suspended HCGs, which are realized by simple fabrication without critical point drying. The HCG-VCSEL achieves a threshold current of about 0.65 m A and a side-mode suppression ratio of 43.6 d B under continuous-wave operation at 25℃. Theoretically the HCG-VCSEL with a λ∕2-cavity for the transverse magnetic polarization has a smaller effective mode length of 1.38 ·(λ∕n). Thus, the relaxation resonance frequency can be increased by 16% compared with that of the conventional VCSEL. The modulation speed of 100 Gbit/s for the HCG-VCSEL is expected in the on–off keying modulation format. Our easy design of HCGVCSELs has great potential for applications in optical interconnects, sensing, illumination, and so on.
基金financial support from the National Natural Science Foundation of China(Nos.61571426,61671435)the National Key Technology R&D Program(No.2015BAI23H00)+1 种基金Beijing Natural Science Foundation(No.4161003)Beijing Key Laboratory of Environmentally Harmful Chemical Analysis
文摘Metal ions are physiologically essential,but excessive metal ions may cause severe risk to plants and animals.Here,we prepared gold nanoclusters（Au NCs） protected by 11-mercaptoundecanoic acid（11-MUA）,which have excellent fluorescence properties for the detection of metal ions.The results showed that the copper ions（Cu^（2＋）） and iron ions（Fe^（3＋）） in the solution have obvious quenching effect on the fluorescence intensity of Au NCs.The detection range of Fe^（3＋） was 0.8-4.5 mmol/L（R^2= 0.992） and 4.5-11.0 mmol/L（R^2= 0.997）.And Cu^（2＋） has a lower linear range（0.1-1.0 mmol/L,R2= 0.993）.When EDTA was added into the reaction system,it was observed that the quenching effect of Cu^（2＋） and Fe^（3＋）on Au NCs showed different phenomenon.Then,the effect of metal ions on the fluorescence of Au NCs was investigated.The selective detection of Cu（2＋） was achieved by EDTA masking of Fe^（3＋）.In addition,we realized the metal ions detection application of Au NCs in the serum
