A low cost and simply fabricated reflective graphene oxide is successfully made. By using this absorber, as well as an end reflector, we obtain a passively mode-locked Yb：LuYSiO5 laser operating at nearly 1 p,m. When...A low cost and simply fabricated reflective graphene oxide is successfully made. By using this absorber, as well as an end reflector, we obtain a passively mode-locked Yb：LuYSiO5 laser operating at nearly 1 p,m. When the pump power is increased up to 5.73 W, stable mode locking is achieved. The central wavelength of the laser spectrum is 1043.2 nm with a pulse duration of 5.0 ps. When the pump power reaches 8.16 W, dual-wavelength mode locking laser pulses at 1036.3 nm and 1043.5 nm are simultaneously detected.展开更多
We demonstrate an erbium-doped ring-cavity fiber laser Q-switched by a graphene oxide-based saturable absorber(GOSA).The GOSA was fabricated by vertically evaporating GO-polyvinylalcohol(GO/PVA)composite dispersion,an...We demonstrate an erbium-doped ring-cavity fiber laser Q-switched by a graphene oxide-based saturable absorber(GOSA).The GOSA was fabricated by vertically evaporating GO-polyvinylalcohol(GO/PVA)composite dispersion,and has a good performance under room temperature.Utilizing a specially fabricated fiber Bragg grating(FBG),stable five-wavelength lasing is realized and stabilized at different pump powers under any polarization.When the pump power increases from 78.4 mW to 379.3 mW,the output power ranging from 1.9 mW to 16.6 mW could be obtained,with pulse duration from 6.8μs to 2.72μs,single pulse energy from 123.73 nJ to 229.74 nJ,and pulse repetition rate from 15.36 kHz to 72.25 kHz.To the best of our knowledge,it is the first simultaneous realization of five-wavelength operation and pulse output in a GO Q-switched all fiber laser system.展开更多
We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical para...We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical parametric oscillator as the pump source.The power of the 2μm dual-wavelength laser was up to 12.33 W with continuous tuning ranges of 1988.0–2196.2 nm/2278.4–2065.6 nm for two waves.Different GaSe cystal lengths have been experimentally investigated for the DFG THz source in order to optimize the THz output power,which was in good agreement with the theoretical analysis.Based on an 8 mm long GaSe crystal,the THz wave was continuously tuned from 0.21 to 3 THz.The maximum THz average power of 1.66μW was obtained at repetition rate of 10 kHz under 1.48 THz.The single pulse energy amounted to 166 pJ and the conversion efficiency from 2 μm laser to THz output was 1.68×10^(-6).The signal-to-noise ratio of the detected THz voltage was 23 dB.The acceptance angle of DFG in the GaSe crystal was measured to be 0.16°.展开更多
All-inorganic halide perovskites(IHP),CsPbX_(3)(X=Cl,Br,I)exhibiting efficient optical emissions within the spectral range of 410 to 730 nm are potential candidates for many optoelectronic devices.Anion alloying of th...All-inorganic halide perovskites(IHP),CsPbX_(3)(X=Cl,Br,I)exhibiting efficient optical emissions within the spectral range of 410 to 730 nm are potential candidates for many optoelectronic devices.Anion alloying of these IHPs is expected to achieve tunable emission wavelength covering the entire visible spectrum.Here,we developed a two-step chemical vapor deposition(CVD)process for growing quaternary IHP CsPbX_(3)(X=Cl/Br and Br/I)alloys.By exploiting the fast diffusion of halide anions in IHPs,the alloy composition can be precisely controlled by the growth time of the respective layers once the growth of the individual ternary IHP is optimized.Hence complexities in the multi-parameter optimization in the conventional CVD growth of quaternary alloys can be mitigated.Using this process,we synthesized single crystalline,homogeneous and thermally stable CsPbCl3_((1−X))Br_(3x)and CsPbBr3_((1−X))I_(3x)perovskites alloy microplates and demonstrated continuously tunable emission covering the spectrum from 428 to 715 nm by varying the halide compositions in the alloys.These alloy microplates also exhibit room temperature amplified spontaneous emissions(ASE)along with strong photonic discharges from the microplate’s edges and hence are potentially useful as a gain medium as well as optical cavities for emissions with wavelengths covering the visible spectrum.展开更多
基金support by the National Natural Science Foundation of China (Grant No. 61078032)the Science and Technology Projects Plan of Jinan City, China (Grant No. 201004007)+2 种基金the State Key Laboratory of Crystal Materials, China (Grant No. KF1201)the Research Grants Council of Hong Kong, China (Grant No. GRF 526511 PolyU code: B-Q26E)the Hong Kong Polytechnic University, China (Grant No. G-YJ20)
文摘A low cost and simply fabricated reflective graphene oxide is successfully made. By using this absorber, as well as an end reflector, we obtain a passively mode-locked Yb：LuYSiO5 laser operating at nearly 1 p,m. When the pump power is increased up to 5.73 W, stable mode locking is achieved. The central wavelength of the laser spectrum is 1043.2 nm with a pulse duration of 5.0 ps. When the pump power reaches 8.16 W, dual-wavelength mode locking laser pulses at 1036.3 nm and 1043.5 nm are simultaneously detected.
基金Supported by the National Key Basic Research and Development Program of China(No 2010CB735904)NSFC(No 61007054)+5 种基金Doctoral Program of High School Research Fund(No 20104408110002)the Improvement and Development Project of Shenzhen Key Lab(No CXB201005240014A)the Science and Technology Project of Shenzhen City(No JC201105170693A)the Key Program of Basic Research Project of Shenzhen(No JC201005250048A)the Applied Technology Developmental Project of Shenzhen University(No 201221)the Research Grants Council of Hong Kong,China(No GRF PolyU 526511).
文摘We demonstrate an erbium-doped ring-cavity fiber laser Q-switched by a graphene oxide-based saturable absorber(GOSA).The GOSA was fabricated by vertically evaporating GO-polyvinylalcohol(GO/PVA)composite dispersion,and has a good performance under room temperature.Utilizing a specially fabricated fiber Bragg grating(FBG),stable five-wavelength lasing is realized and stabilized at different pump powers under any polarization.When the pump power increases from 78.4 mW to 379.3 mW,the output power ranging from 1.9 mW to 16.6 mW could be obtained,with pulse duration from 6.8μs to 2.72μs,single pulse energy from 123.73 nJ to 229.74 nJ,and pulse repetition rate from 15.36 kHz to 72.25 kHz.To the best of our knowledge,it is the first simultaneous realization of five-wavelength operation and pulse output in a GO Q-switched all fiber laser system.
基金National Basic Research Program of China(973)(2014CB339802,2015CB755403)National key research and development projects(2016YFC0101001)+5 种基金National Key Technology R&D Program of China(2014BAI04B05,2015BAI01B01)National Natural Science Foundation of China(NSFC)(61107086,61471257,81402067)Natural Science Foundation of Tianjin City(14JCQNJC02200)Postdoctoral Science Foundation of Chongqing(Xm2016021)Joint Incubation Project of Southwest Hospital(SWH2016LHJC-04,SWH2016LHJC-01)Science and Technology Support Program of Tianjin(13ZCZDSF02300)
文摘We have demonstrated a high-average-power,high-repetition-rate optical terahertz(THz)source based on difference frequency generation(DFG)in the GaSe crystal by using a near-degenerate 2μm intracavity KTP optical parametric oscillator as the pump source.The power of the 2μm dual-wavelength laser was up to 12.33 W with continuous tuning ranges of 1988.0–2196.2 nm/2278.4–2065.6 nm for two waves.Different GaSe cystal lengths have been experimentally investigated for the DFG THz source in order to optimize the THz output power,which was in good agreement with the theoretical analysis.Based on an 8 mm long GaSe crystal,the THz wave was continuously tuned from 0.21 to 3 THz.The maximum THz average power of 1.66μW was obtained at repetition rate of 10 kHz under 1.48 THz.The single pulse energy amounted to 166 pJ and the conversion efficiency from 2 μm laser to THz output was 1.68×10^(-6).The signal-to-noise ratio of the detected THz voltage was 23 dB.The acceptance angle of DFG in the GaSe crystal was measured to be 0.16°.
文摘All-inorganic halide perovskites(IHP),CsPbX_(3)(X=Cl,Br,I)exhibiting efficient optical emissions within the spectral range of 410 to 730 nm are potential candidates for many optoelectronic devices.Anion alloying of these IHPs is expected to achieve tunable emission wavelength covering the entire visible spectrum.Here,we developed a two-step chemical vapor deposition(CVD)process for growing quaternary IHP CsPbX_(3)(X=Cl/Br and Br/I)alloys.By exploiting the fast diffusion of halide anions in IHPs,the alloy composition can be precisely controlled by the growth time of the respective layers once the growth of the individual ternary IHP is optimized.Hence complexities in the multi-parameter optimization in the conventional CVD growth of quaternary alloys can be mitigated.Using this process,we synthesized single crystalline,homogeneous and thermally stable CsPbCl3_((1−X))Br_(3x)and CsPbBr3_((1−X))I_(3x)perovskites alloy microplates and demonstrated continuously tunable emission covering the spectrum from 428 to 715 nm by varying the halide compositions in the alloys.These alloy microplates also exhibit room temperature amplified spontaneous emissions(ASE)along with strong photonic discharges from the microplate’s edges and hence are potentially useful as a gain medium as well as optical cavities for emissions with wavelengths covering the visible spectrum.
