In this review paper, we introduce a self-phase controlled stimulated Brillouin scattering phase conjugate mirror(SCSBS-PCM) and the Kumgang laser. The SC-SBS-PCM was proposed and demonstrated its success at the acade...In this review paper, we introduce a self-phase controlled stimulated Brillouin scattering phase conjugate mirror(SCSBS-PCM) and the Kumgang laser. The SC-SBS-PCM was proposed and demonstrated its success at the academic low power level, ~100 mJ@10 Hz. The Kumgang laser is under development to verify whether the SC-SBS-PCM is operable at the k W level. It is a 4 kW beam combination laser combining four 1 k W beams using the SC-SBS-PCM. If the Kumgang laser functions successfully, it will be the most important step towards a Dream laser, a hypothetical laser with unlimited power and a high repetition rate.展开更多
25 fs pulses with energy up to 0.8 mJ from a multi-pass amplifier system have been spectrally broadened from 460 nm to 950 nm due to strong self-phase modulation(SPM) effect in a gas filled hollow fiber.Using a set of...25 fs pulses with energy up to 0.8 mJ from a multi-pass amplifier system have been spectrally broadened from 460 nm to 950 nm due to strong self-phase modulation(SPM) effect in a gas filled hollow fiber.Using a set of chirped mirrors,the ul-tra-broadband dispersion compensation was achieved,and the compressed pulses reached their transform limit.Under optimized conditions we achieved pulses with duration of 5.1 fs and with energy of 400 μJ,corresponding to the peak power up to 80 GW.展开更多
We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining...We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining second harmonic generation in the BBO crystal with self-phase modulation in the fused-silica substrate,we efficiently generate millijoule-level broadband violet pulses from a single optical component.The second harmonic spectrum covers a range from long wave ultraviolet(down to 310 nm)to visible(up to 550 nm)with a bandwidth of 65 nm.Subsequently,we compress the second harmonic beam to a duration of 4.8 fs with a pulse energy of 0.64 mJ(5 fs with a pulse energy of 1.05 mJ)using chirped mirrors.The all-solid free-space apparatus is compact,robust and pulse energy scalable,making it highly advantageous for generating intense second harmonic pulses from near-infrared femtosecond lasers in the sub-5 fs regime.展开更多
High-peak-power transform-limited narrow-linewidth nanosecond all-fiber lasers are desired in a range of applications.However,their linewidths will be broadened by self-phase modulation(SPM).We propose a novel concept...High-peak-power transform-limited narrow-linewidth nanosecond all-fiber lasers are desired in a range of applications.However,their linewidths will be broadened by self-phase modulation(SPM).We propose a novel concept that generates transform-limited laser pulses by temporally shaping the pulse seed.The impact of the pulse shape on SPM-induced spectral broadening was studied numerically and experimentally.It was found theoretically that the square-shape pulsed laser is immune to SPM-induced spectral broadening.Based on this principle,we built a high-peak-power,linearly polarized,square-shape nanosecond all-fiber laser in a master oscillator power amplifier(MOPA)configuration.Stimulated Brillouin scattering(SBS)limited peak powers of 4.02 kW,5.06 kW,6.52 kW and 9.30 kW were obtained at pulse widths of 8 ns,7 ns,6 ns and 5 ns.Thanks to the square-shape pulsed seed,the linewidths at maximum peak power remained at 129.5 MHz,137.6 MHz,156.2 MHz and 200.1 MHz,respectively,close to the transform-limited values of110.8 MHz,126.6 MHz,147.7 MHz and 177.3 MHz.展开更多
An exceptionally high stimulated Raman scattering[SRS]conversion efficiency to the first Stokes component associated with the secondary[low-frequency and low intensity]vibrational mode v2[~330 cm^[-1]]was observed in ...An exceptionally high stimulated Raman scattering[SRS]conversion efficiency to the first Stokes component associated with the secondary[low-frequency and low intensity]vibrational mode v2[~330 cm^[-1]]was observed in a BaWO4 crystal in a highly transient regime of interaction.The effect takes place in the range of pump pulse energy from~0.1 to~0.5μJ with maximum energy conversion efficiency up to 35%at 0.2μJ.The nature of the observed effects is explained by interference of SRS and self-phase modulation,where the latter is related to a noninstantaneous orientational Kerr nonlinearity in the BaWO4 crystal.展开更多
The post-compression technique based on self-phase modulation of high-energy pulses leads to an increase in achievable peak power and intensity.Typically,the pulses considered in experiments have been less than 100 fs...The post-compression technique based on self-phase modulation of high-energy pulses leads to an increase in achievable peak power and intensity.Typically,the pulses considered in experiments have been less than 100 fs in duration.Here,the method is applied to the ELFIE laser system at the LULI facility,for a pulse of 7 J energy and an initial measured duration of 350 fs.A 5-mm-thick fused silica window and a 2 mm cyclic-olefin polymer were used as optical nonlinear materials.The 9 cm diameter beam was spectrally broadened to a bandwidth corresponding to 124 fs Fourier-limited pulse duration,and then it was partly post-compressed to 200 fs.After measuring the spatial spectra of the beam fluence,a uniform gain factor of 4 increase in the fluctuations over the studied range of frequencies is observed,due to small-scale self-focusing.展开更多
This paper studied the influence of return to zero-differential phase-shift-keying （RZ-DPSK） data format on techniques of pre-, post- and pre/post combination dispersion compensation for faithful transmission of opt...This paper studied the influence of return to zero-differential phase-shift-keying （RZ-DPSK） data format on techniques of pre-, post- and pre/post combination dispersion compensation for faithful transmission of optical signal at 80 and 100 Gbits/s channel bit rate via simulation. The purpose of this study was to find out the dispersion compensation techniques for optimal transmis- sion with the interaction effects of self-phase modulation （SPM） and amplifier spontaneous emission （ASE） for RZ- DPSK encoded optical data. By the simulation method, it was found out that the RZ-DPSK data format can be allowed with a transmission distance of about 700 km of standard single mode fiber （SMF） at 100 Gbits/s, and it can be provided with farther transmission distance of more than 1000 km at 80 Gbits/s with the combination of the pre- and post-compensation technique. To efficiently suppress the effect of ASE and improve optical signal-to- noise ratio （OSNR）, the bandwidth frequency of optical receiver filter was found to be at least equal to bit rate.展开更多
The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation res...The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.展开更多
We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the Swiss FEL X-ray free-electron laser facility.A single stage consisti...We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the Swiss FEL X-ray free-electron laser facility.A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30-fs pulses with 800-nm center wavelength to sub-10-fs duration.We also demonstrate a two-stage implementation to compress the pulses further to sub-5-fs duration.With the two-stage setup,the generated supercontinuum includes wavelengths ranging from 500 to 1100 nm.The multiplate setup is compact,robust,and stable,which makes it ideal for applications at free-electron laser facilities such as pump-probe experiments and laser-arrival timing tools.展开更多
MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXen...MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXene nanosheets dispersed in deionized water in the visible to near-infrared regime,highlighting the broadband nonlinear optical(NLO)response of Ti2CTx MXene.Using ultrafast pulsed laser excitation,the nonlinear refractive index n2 and the thirdorder nonlinear susceptibility χ^(3)monolayer of Ti2CTx MXene were measured to be^10^−13 m^2/W and ~10^−10 esu,respectively.Leveraging the large optical nonlinearity of Ti2CTx MXene,an all-optical modulator in the visible regime was fabricated based on the spatial cross-phase modulation effect.This work suggests that 2D MXenes are ideal broadband NLO materials with excellent prospects in NLO applications.展开更多
In this paper the phase-dependent features of ultrashort laser pulse resonant propagation in a two-level dipolar molecule are demonstrated by solving full Maxwell-Bloch equations. The electronic properties of dipolar ...In this paper the phase-dependent features of ultrashort laser pulse resonant propagation in a two-level dipolar molecule are demonstrated by solving full Maxwell-Bloch equations. The electronic properties of dipolar molecule 4-trans-[p-（N, N-Di-n-butylamino）-p-stilbenylvinyl] pyridine （DBASVP） molecule, one-dimensional asymmetric organic molecule, is calculated by density functional theory at ab initio level. The numerical results show that the carrier propagation and the spectrum evolution of the pulse are sensitive to its initial phase and the phase sensitivity is more obvious for larger area pulse. The phase-dependent feature is more evident in dipolar molecule because the permanent dipole moment makes the nonlinear effects stronger.展开更多
A thermal lens technique is adopted using a single modulated continuous wave （cw） 532-nm laser beam to evaluate the nonlinear refractive index n2, and the thermo-optic coefficient dn/dT, in polymer Poly （1-naphthyl...A thermal lens technique is adopted using a single modulated continuous wave （cw） 532-nm laser beam to evaluate the nonlinear refractive index n2, and the thermo-optic coefficient dn/dT, in polymer Poly （1-naphthyl methacrylate） （P-1-NM） dissolved in chloroform, tetrahydrofuran （THF）, and dimethyl sulfoxide （DMSO） solvents. The results are compared with Z-scan and diffraction ring techniques. The comparison reveals the effectiveness and the simplicity of the TTL modulation technique. The physical origin is discussed for the obtained results.展开更多
基金supported by the ‘Dual Use Technology Program’ at the Agency for Defense Development (ADD) of the Republic of Korea (UM12012RD1)
文摘In this review paper, we introduce a self-phase controlled stimulated Brillouin scattering phase conjugate mirror(SCSBS-PCM) and the Kumgang laser. The SC-SBS-PCM was proposed and demonstrated its success at the academic low power level, ~100 mJ@10 Hz. The Kumgang laser is under development to verify whether the SC-SBS-PCM is operable at the k W level. It is a 4 kW beam combination laser combining four 1 k W beams using the SC-SBS-PCM. If the Kumgang laser functions successfully, it will be the most important step towards a Dream laser, a hypothetical laser with unlimited power and a high repetition rate.
基金the National Natural Science Foundation of China(Grant Nos.60608003,60490280,60225005 and 60621063)
文摘25 fs pulses with energy up to 0.8 mJ from a multi-pass amplifier system have been spectrally broadened from 460 nm to 950 nm due to strong self-phase modulation(SPM) effect in a gas filled hollow fiber.Using a set of chirped mirrors,the ul-tra-broadband dispersion compensation was achieved,and the compressed pulses reached their transform limit.Under optimized conditions we achieved pulses with duration of 5.1 fs and with energy of 400 μJ,corresponding to the peak power up to 80 GW.
文摘We demonstrate the generation,spectral broadening and post-compression of second harmonic pulses using a thin beta barium borate(BBO)crystal on a fused-silica substrate as the nonlinear interaction medium.By combining second harmonic generation in the BBO crystal with self-phase modulation in the fused-silica substrate,we efficiently generate millijoule-level broadband violet pulses from a single optical component.The second harmonic spectrum covers a range from long wave ultraviolet(down to 310 nm)to visible(up to 550 nm)with a bandwidth of 65 nm.Subsequently,we compress the second harmonic beam to a duration of 4.8 fs with a pulse energy of 0.64 mJ(5 fs with a pulse energy of 1.05 mJ)using chirped mirrors.The all-solid free-space apparatus is compact,robust and pulse energy scalable,making it highly advantageous for generating intense second harmonic pulses from near-infrared femtosecond lasers in the sub-5 fs regime.
基金supported by the National Natural Science Foundation of China(Nos.61705265 and 61705264)the National Key R&D Programme of China(No.2017YFF0104603)the China Postdoctoral Science Foundation(No.2017M620070)
文摘High-peak-power transform-limited narrow-linewidth nanosecond all-fiber lasers are desired in a range of applications.However,their linewidths will be broadened by self-phase modulation(SPM).We propose a novel concept that generates transform-limited laser pulses by temporally shaping the pulse seed.The impact of the pulse shape on SPM-induced spectral broadening was studied numerically and experimentally.It was found theoretically that the square-shape pulsed laser is immune to SPM-induced spectral broadening.Based on this principle,we built a high-peak-power,linearly polarized,square-shape nanosecond all-fiber laser in a master oscillator power amplifier(MOPA)configuration.Stimulated Brillouin scattering(SBS)limited peak powers of 4.02 kW,5.06 kW,6.52 kW and 9.30 kW were obtained at pulse widths of 8 ns,7 ns,6 ns and 5 ns.Thanks to the square-shape pulsed seed,the linewidths at maximum peak power remained at 129.5 MHz,137.6 MHz,156.2 MHz and 200.1 MHz,respectively,close to the transform-limited values of110.8 MHz,126.6 MHz,147.7 MHz and 177.3 MHz.
基金funded by the Russian Science Foundation(No.22-79-10068)。
文摘An exceptionally high stimulated Raman scattering[SRS]conversion efficiency to the first Stokes component associated with the secondary[low-frequency and low intensity]vibrational mode v2[~330 cm^[-1]]was observed in a BaWO4 crystal in a highly transient regime of interaction.The effect takes place in the range of pump pulse energy from~0.1 to~0.5μJ with maximum energy conversion efficiency up to 35%at 0.2μJ.The nature of the observed effects is explained by interference of SRS and self-phase modulation,where the latter is related to a noninstantaneous orientational Kerr nonlinearity in the BaWO4 crystal.
基金This work was supported by the Center of Excellence‘Center of Photonics’,Ministry of Science and Higher Education of the Russian Federation(contract No.075-15-2020-906)Project ELI-RO 16/2020 SBUF funded by the Institute for Atomic Physics(IFA)and by the Council for Doctoral Studies(CSUD),University of Bucharest.
文摘The post-compression technique based on self-phase modulation of high-energy pulses leads to an increase in achievable peak power and intensity.Typically,the pulses considered in experiments have been less than 100 fs in duration.Here,the method is applied to the ELFIE laser system at the LULI facility,for a pulse of 7 J energy and an initial measured duration of 350 fs.A 5-mm-thick fused silica window and a 2 mm cyclic-olefin polymer were used as optical nonlinear materials.The 9 cm diameter beam was spectrally broadened to a bandwidth corresponding to 124 fs Fourier-limited pulse duration,and then it was partly post-compressed to 200 fs.After measuring the spatial spectra of the beam fluence,a uniform gain factor of 4 increase in the fluctuations over the studied range of frequencies is observed,due to small-scale self-focusing.
文摘This paper studied the influence of return to zero-differential phase-shift-keying （RZ-DPSK） data format on techniques of pre-, post- and pre/post combination dispersion compensation for faithful transmission of optical signal at 80 and 100 Gbits/s channel bit rate via simulation. The purpose of this study was to find out the dispersion compensation techniques for optimal transmis- sion with the interaction effects of self-phase modulation （SPM） and amplifier spontaneous emission （ASE） for RZ- DPSK encoded optical data. By the simulation method, it was found out that the RZ-DPSK data format can be allowed with a transmission distance of about 700 km of standard single mode fiber （SMF） at 100 Gbits/s, and it can be provided with farther transmission distance of more than 1000 km at 80 Gbits/s with the combination of the pre- and post-compensation technique. To efficiently suppress the effect of ASE and improve optical signal-to- noise ratio （OSNR）, the bandwidth frequency of optical receiver filter was found to be at least equal to bit rate.
基金Project supported by the National Natural Science Foundation of China （Grant No 60577033）, the Specialized Research Fund for the Doctoral Program of Higher Education （Grant No 20050003010） and the Basic Research Foundation of Tsinghua National Laboratory for Information Science and Technology.
文摘The influence of degenerate four-wave mixing （FWM） on the performance of supercontinuum-based multiwavelength optical source has been investigated in detail experimentally and theoretically. Numerical simulation results show that the degenerate FWM effect has a deteriorative influence on the spectral uniformity and the optical signal-to-noise ratio （OSNR） of supercontinuum-based optical source, and by suppressing degenerate FWM effect the performance enhancement of the supercontinuum can be achieved successfully. These results are also confirmed by our experiments. Experimentally, by suppressing degenerate FWM the crosstalk of adjacent channels to the filtered channel can be reduced by as much as 15 dB, and consequently the measured receiver sensitivity at 10 Gbit/s for the filtered optical source is improved from -1.7 to -17.8 dBm.
文摘We report on compact and robust supercontinuum generation and post-compression using transmission of light through multiple thin solid plates at the Swiss FEL X-ray free-electron laser facility.A single stage consisting of three thin plates followed by a chirped mirror compressor achieves compression of initially 30-fs pulses with 800-nm center wavelength to sub-10-fs duration.We also demonstrate a two-stage implementation to compress the pulses further to sub-5-fs duration.With the two-stage setup,the generated supercontinuum includes wavelengths ranging from 500 to 1100 nm.The multiplate setup is compact,robust,and stable,which makes it ideal for applications at free-electron laser facilities such as pump-probe experiments and laser-arrival timing tools.
基金National Science Foundation,Grant/Award Number:MoMS 1930881China Scholarship Council,Grant/Award Number:201706130028+6 种基金National Natural Science Fund Foundation of China,Grant/Award Number:61775056Natural Science Foundation of Hunan Province,Grant/Award Number:2017JJ1013Research Fund of Science and Technology on Plasma Physics Laboratory,Grant/Award Number:6142A0403050717This work was supported by the National Natural Science Foundation of China(NSFC)(61775056)Natural Science Foundation of Hunan Province(2017JJ1013)Research Fund of Science and Technology on Plasma Physics Laboratory(6142A0403050717)The support provided by China Scholarship Council(CSC)during a visit of Jun Yi to Clemson University is acknowledged.This material is based upon work supported by the National Science Foundation under Grant No.MoMS 1930881.
文摘MXenes,a new class of 2D transition metal carbides,nitrides,and carbonitrides,have attracted much attention due to their outstanding properties.Here,we report the broadband spatial self-phase modulation of Ti2CTx MXene nanosheets dispersed in deionized water in the visible to near-infrared regime,highlighting the broadband nonlinear optical(NLO)response of Ti2CTx MXene.Using ultrafast pulsed laser excitation,the nonlinear refractive index n2 and the thirdorder nonlinear susceptibility χ^(3)monolayer of Ti2CTx MXene were measured to be^10^−13 m^2/W and ~10^−10 esu,respectively.Leveraging the large optical nonlinearity of Ti2CTx MXene,an all-optical modulator in the visible regime was fabricated based on the spatial cross-phase modulation effect.This work suggests that 2D MXenes are ideal broadband NLO materials with excellent prospects in NLO applications.
基金Froject supported by the Shandong Natural Science Foundation （Grant No Y2004A08）, University Doctoral Subject Special Science and Technology Foundation （Grant No 20040445001） and the Key Laboratory for High Intensity 0ptics of Shanghai Institute of 0ptics and Fine Mechanics, Chinese Academy of Sciences.
文摘In this paper the phase-dependent features of ultrashort laser pulse resonant propagation in a two-level dipolar molecule are demonstrated by solving full Maxwell-Bloch equations. The electronic properties of dipolar molecule 4-trans-[p-（N, N-Di-n-butylamino）-p-stilbenylvinyl] pyridine （DBASVP） molecule, one-dimensional asymmetric organic molecule, is calculated by density functional theory at ab initio level. The numerical results show that the carrier propagation and the spectrum evolution of the pulse are sensitive to its initial phase and the phase sensitivity is more obvious for larger area pulse. The phase-dependent feature is more evident in dipolar molecule because the permanent dipole moment makes the nonlinear effects stronger.
文摘A thermal lens technique is adopted using a single modulated continuous wave （cw） 532-nm laser beam to evaluate the nonlinear refractive index n2, and the thermo-optic coefficient dn/dT, in polymer Poly （1-naphthyl methacrylate） （P-1-NM） dissolved in chloroform, tetrahydrofuran （THF）, and dimethyl sulfoxide （DMSO） solvents. The results are compared with Z-scan and diffraction ring techniques. The comparison reveals the effectiveness and the simplicity of the TTL modulation technique. The physical origin is discussed for the obtained results.
