GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ri...GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of a blue-violet LD are investigated under direct-current injection at room temperature(25 °C). The stimulated emission wavelength and peak optical power of the LD are around 413 nm and over 600 mW, respectively.In addition, the threshold current density and voltage are as small as 1.46 kA/cm^2 and 4.1 V, respectively. Moreover, the lifetime is longer than 1000 hours under room-temperature continuous-wave operation.展开更多
The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two di...The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two different temperatures, the same-temperature growth of InGaN well and GaN barrier layers has a positive effect on the threshold current and slope efficiency of laser diodes, indicating that the quality of MQWs is improved. In addition, the performance of GaN laser diodes could be further improved by increasing Al content in the AlGaN EBL due to the fact that the electron leakage current could be reduced by properly increasing the barrier height of AlGaN EBL. The violet laser diode with a peak output power of 20 W is obtained.展开更多
Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG ...Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG laser. Distributed feedback dye laser （DFDL） action was induced in the dye mixture using a prism arrangement both in the donor and acceptor regions by an energy transfer mechanism. Theoretically, the characteristics of acceptor and donor DFDLs, and the dependence of their pulse widths and output powers on acceptor-donor concentrations and pump power, were studied. Experimentally, the output energy of DFDL was measured at the emission peaks of donor and acceptor dyes for different pump powers and different acceptor-donor concentrations. Tuning of the output wavelength was achieved by varying the period of the gain modulation of the laser medium. The laser wavelength showed continuous tunability from 563 nm to 648 nm.展开更多
The laser irradiation effect on the SERS intensity for Ag film is discussed using crystal violet (CV) as a probe. The thickness of silver film,the etching time of the glass slide by gaseous hydrogen fluoride, and the ...The laser irradiation effect on the SERS intensity for Ag film is discussed using crystal violet (CV) as a probe. The thickness of silver film,the etching time of the glass slide by gaseous hydrogen fluoride, and the laser irradiation time for different amounts of CV on silver films were investigated. The laser burn out model was proposed to explain the dependence of the SERS intensity of CV on the laser irradiation time.展开更多
Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are ur...Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are urgent.Here,another 2D material,violet phosphorus(VP)nanoflake is investigated as gas sensing material.The VP nanoflakes have been effectively ablated to have layers of 1–5 layers by laser ablation in glycol.The VP nanoflakes are combined with graphene to form VP/G heterostructuresbased NO sensor.An ultra-high gauge factor of 3×10^(7)for ppb-level sensing and high resistance response of 59.21%with ultra-short recovery time of 6s for ppm-level sensing have been obtained.The sensing mechanism is also analysed by density functional theory(DFT)calculations.The adsorption energy of VP/G is calculated to be-0.788 e V,resulting in electrons migration from P to N to form a P-N bond in the gap between VP and graphene sheet.This work provides a facile approach to ablate VP for mass production.The as-produced structures have also provided potential gas sensors with ultrasensitive performance as ppb-level room-temperature sensors.展开更多
基金supported by the National Key R&D Program of China (Nos. 2016YFB0401801, 2016YFB0400803)the Science Challenge Project (No. TZ2016003)+1 种基金the National Natural Science Foundation of China (Nos. 61674138, 61674139, 61604145, 61574135, 61574134, 61474142, 61474110)the Beijing Municipal Science and Technology Project (No. Z161100002116037)
文摘GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of a blue-violet LD are investigated under direct-current injection at room temperature(25 °C). The stimulated emission wavelength and peak optical power of the LD are around 413 nm and over 600 mW, respectively.In addition, the threshold current density and voltage are as small as 1.46 kA/cm^2 and 4.1 V, respectively. Moreover, the lifetime is longer than 1000 hours under room-temperature continuous-wave operation.
基金Supported by the National Key Research and Development Program of China under Grant No 2016YFB0401801the National Natural Science Foundation of China under Grant Nos 61574135,61574134,61474142,61474110,61377020,61376089,and 61223005the One Hundred Person Project of the Chinese Academy of Sciences
文摘The influences of InGaN/GaN multiple quantum wells (MQWs) and AlGaN electron-blocking layers (EBL) on the performance of GaN-based violet laser diodes are investigated. Compared with the InGaN/GaN MQWs grown at two different temperatures, the same-temperature growth of InGaN well and GaN barrier layers has a positive effect on the threshold current and slope efficiency of laser diodes, indicating that the quality of MQWs is improved. In addition, the performance of GaN laser diodes could be further improved by increasing Al content in the AlGaN EBL due to the fact that the electron leakage current could be reduced by properly increasing the barrier height of AlGaN EBL. The violet laser diode with a peak output power of 20 W is obtained.
文摘Laser action in methyl methacrylate （MMA） co-doped with sulforhodamine B and crystal violet dyes was investi- gated. The dye mixture was incorporated into a solid polymeric matrix and was pumped by a 532-nm Nd：YAG laser. Distributed feedback dye laser （DFDL） action was induced in the dye mixture using a prism arrangement both in the donor and acceptor regions by an energy transfer mechanism. Theoretically, the characteristics of acceptor and donor DFDLs, and the dependence of their pulse widths and output powers on acceptor-donor concentrations and pump power, were studied. Experimentally, the output energy of DFDL was measured at the emission peaks of donor and acceptor dyes for different pump powers and different acceptor-donor concentrations. Tuning of the output wavelength was achieved by varying the period of the gain modulation of the laser medium. The laser wavelength showed continuous tunability from 563 nm to 648 nm.
文摘The laser irradiation effect on the SERS intensity for Ag film is discussed using crystal violet (CV) as a probe. The thickness of silver film,the etching time of the glass slide by gaseous hydrogen fluoride, and the laser irradiation time for different amounts of CV on silver films were investigated. The laser burn out model was proposed to explain the dependence of the SERS intensity of CV on the laser irradiation time.
基金the funding support by National Natural Science Foundation of China(Nos.61705125,22175136)Open Foundation of State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Guangxi University(No.2022GXYSOF15)。
文摘Two dimensional(2D)materials are promising gas sensing materials,but the most of them need to be heated to show promising sensing performance.Sensing structures with high sensing performance at room-temperature are urgent.Here,another 2D material,violet phosphorus(VP)nanoflake is investigated as gas sensing material.The VP nanoflakes have been effectively ablated to have layers of 1–5 layers by laser ablation in glycol.The VP nanoflakes are combined with graphene to form VP/G heterostructuresbased NO sensor.An ultra-high gauge factor of 3×10^(7)for ppb-level sensing and high resistance response of 59.21%with ultra-short recovery time of 6s for ppm-level sensing have been obtained.The sensing mechanism is also analysed by density functional theory(DFT)calculations.The adsorption energy of VP/G is calculated to be-0.788 e V,resulting in electrons migration from P to N to form a P-N bond in the gap between VP and graphene sheet.This work provides a facile approach to ablate VP for mass production.The as-produced structures have also provided potential gas sensors with ultrasensitive performance as ppb-level room-temperature sensors.
