Multilayer black phosphorus(BP) nanoplatelets of different thicknesses were prepared by the liquid phase exfoliation method and deposited onto yttrium aluminum garnet substrates to form saturable absorbers(SAs). These...Multilayer black phosphorus(BP) nanoplatelets of different thicknesses were prepared by the liquid phase exfoliation method and deposited onto yttrium aluminum garnet substrates to form saturable absorbers(SAs). These were characterized with respect to their thickness-dependent saturable absorption properties at 3 μm. The BP-SAs were employed in a passively Q-switched Er:Lu_2O_3 laser at 2.84 μm. By using BP exfoliated in different solvents,stable pulses as short as 359 ns were generated at an average output power of up to 755 m W. The repetition rate in the experiment was 107 k Hz, corresponding to a pulse energy of 7.1 μJ. These results prove that BP-SAs have a great potential for optical modulation in the mid-infrared range.展开更多
Tailoring the properties of the driving laser to the need of applications often requires compromises among laser stability,high peak and average power levels,pulse duration,and spectral bandwidth.For instance,spectros...Tailoring the properties of the driving laser to the need of applications often requires compromises among laser stability,high peak and average power levels,pulse duration,and spectral bandwidth.For instance,spectroscopy with optical frequency combs in the extreme/visible ultraviolet spectral region requires a high peak power of the near-IR driving laser,and therefore high average power,pulse duration of a few tens of fs,and maximal available spectral bandwidth.Contrarily,the parametric conversion efficiency is higher for pulses with a duration in the 100-fs range due to temporal walk-off and coating limitations.Here we suggest an approach to adjust the spectral characteristics of high-power chirped-pulse amplification(CPA)to the requirements of different nonlinear frequency converters while preserving the low-phase-noise(PN)properties of the system.To achieve spectral tunability,we installed a mechanical spectral shaper in a free-space section of the stretcher of an in-house-developed ytterbium-fiber-based CPA system.The CPA system delivers 100 W of average power at a repetition rate of 132.4 MHz.While gaining control over the spectral properties,we preserve the relative-intensity-noise and PN properties of the system.The high-power CPA can easily be adjusted to deliver either a spectrum ideal for mid-IR light generation(full width at half maximum of∼11 nm,compressed pulse duration of 230 fs)or a spectrum ideal for highly nonlinear processes such as high-harmonic generation(−10 dB level of>50 nm,transform-limited pulse duration of∼65 fs).展开更多
基金China Postdoctoral Science Foundation(2014M561921,2015T80713)Independent Innovation Foundation of Shandong University(IIFSU)(2082014TB011)+2 种基金Innovation Foundation of the 46th Institute of China Electronics Technology Group Corporation(CJ20130302)National Natural Science Foundation of China(NSFC))(61308020)Deutsche Forschungsgemeinschaft(DFG)(FKZ13N13050)
文摘Multilayer black phosphorus(BP) nanoplatelets of different thicknesses were prepared by the liquid phase exfoliation method and deposited onto yttrium aluminum garnet substrates to form saturable absorbers(SAs). These were characterized with respect to their thickness-dependent saturable absorption properties at 3 μm. The BP-SAs were employed in a passively Q-switched Er:Lu_2O_3 laser at 2.84 μm. By using BP exfoliated in different solvents,stable pulses as short as 359 ns were generated at an average output power of up to 755 m W. The repetition rate in the experiment was 107 k Hz, corresponding to a pulse energy of 7.1 μJ. These results prove that BP-SAs have a great potential for optical modulation in the mid-infrared range.
文摘Tailoring the properties of the driving laser to the need of applications often requires compromises among laser stability,high peak and average power levels,pulse duration,and spectral bandwidth.For instance,spectroscopy with optical frequency combs in the extreme/visible ultraviolet spectral region requires a high peak power of the near-IR driving laser,and therefore high average power,pulse duration of a few tens of fs,and maximal available spectral bandwidth.Contrarily,the parametric conversion efficiency is higher for pulses with a duration in the 100-fs range due to temporal walk-off and coating limitations.Here we suggest an approach to adjust the spectral characteristics of high-power chirped-pulse amplification(CPA)to the requirements of different nonlinear frequency converters while preserving the low-phase-noise(PN)properties of the system.To achieve spectral tunability,we installed a mechanical spectral shaper in a free-space section of the stretcher of an in-house-developed ytterbium-fiber-based CPA system.The CPA system delivers 100 W of average power at a repetition rate of 132.4 MHz.While gaining control over the spectral properties,we preserve the relative-intensity-noise and PN properties of the system.The high-power CPA can easily be adjusted to deliver either a spectrum ideal for mid-IR light generation(full width at half maximum of∼11 nm,compressed pulse duration of 230 fs)or a spectrum ideal for highly nonlinear processes such as high-harmonic generation(−10 dB level of>50 nm,transform-limited pulse duration of∼65 fs).
