Combining high peak power and high average power has long been a key challenge of ultrafast laser technology,crucial for applications such as laser-plasma acceleration and strong-field physics.A promising solution lie...Combining high peak power and high average power has long been a key challenge of ultrafast laser technology,crucial for applications such as laser-plasma acceleration and strong-field physics.A promising solution lies in post-compressed ytterbium lasers,but scaling these to high pulse energies presents a major bottleneck.Post-compression techniques,particularly Herriott-type multi-pass cells(MPCs),have enabled large peak power boosts at high average powers but their pulse energy acceptance reaches practical limits defined by setup size and coating damage threshold.In this work,we address this challenge and demonstrate,to our knowledge,a novel type of compact,energy-scalable MPC(CMPC).By employing a novel MPC configuration and folding the beam path,the CMPC introduces a new degree of freedom for downsizing the setup length,enabling compact setups even for large pulse energies.We experimentally and numerically verify the CMPC approach,demonstrating post-compression of 8 m J pulses from 1 ps down to 51 fs in atmospheric air using a cell roughly 45 cm in length at low fluence values.Additionally,we discuss the potential for energy scaling up to 200 m J with a setup size reaching2.5 m.Our work presents a new approach to high-energy post-compression,with up-scaling potential far beyond the demonstrated parameters.This opens new routes for achieving the high peak and average powers necessary for demanding applications of ultrafast lasers.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
As ultrafast laser technology advances towards ever higher peak and average powers,generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge.Here,we pr...As ultrafast laser technology advances towards ever higher peak and average powers,generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge.Here,we present a very compact and highly robust method to compress 1.24 ps pulses to 39fs by means of only a single spectral broadening stage which neither requires vacuum parts nor custom-made optics.Our approach is based on the hybridization of the multiplate continuum and.the multipass cell spectral broadening techniques.Their combination leads to significantly higher spectral broadening factors in bulk material than what has been reported from either method alone.Moreover,our approach efficiently suppresses adverse features of single-pass bulk spectral broadening.We use a burst-mode Yb:YAG laser emitting pulses with 80 MW peak power that are enhanced to more than 1 GW after postcompression.With only 0.19%rms pulse-to-pulse energy fluctuations,the technique exhibits excellent stability.Furthermore,we have measured state-of-the-art spectral-spatial homogeneity and good beam quality of M^(2)=1.2 up to a spectral broadening factor of 30.Due to the method's simplicity,compactness,and scalability,it is highly attractive for turning a picosecond laser into an ultrafast light source that generates pulses of only a few tens of femtoseconds duration.展开更多
基金Helmholtz-Lund International Graduate School(HIRS-0018)Vetenskapsr?det/Swedish Research Council(2022-03519)。
文摘Combining high peak power and high average power has long been a key challenge of ultrafast laser technology,crucial for applications such as laser-plasma acceleration and strong-field physics.A promising solution lies in post-compressed ytterbium lasers,but scaling these to high pulse energies presents a major bottleneck.Post-compression techniques,particularly Herriott-type multi-pass cells(MPCs),have enabled large peak power boosts at high average powers but their pulse energy acceptance reaches practical limits defined by setup size and coating damage threshold.In this work,we address this challenge and demonstrate,to our knowledge,a novel type of compact,energy-scalable MPC(CMPC).By employing a novel MPC configuration and folding the beam path,the CMPC introduces a new degree of freedom for downsizing the setup length,enabling compact setups even for large pulse energies.We experimentally and numerically verify the CMPC approach,demonstrating post-compression of 8 m J pulses from 1 ps down to 51 fs in atmospheric air using a cell roughly 45 cm in length at low fluence values.Additionally,we discuss the potential for energy scaling up to 200 m J with a setup size reaching2.5 m.Our work presents a new approach to high-energy post-compression,with up-scaling potential far beyond the demonstrated parameters.This opens new routes for achieving the high peak and average powers necessary for demanding applications of ultrafast lasers.
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).
文摘As ultrafast laser technology advances towards ever higher peak and average powers,generating sub-50 fs pulses from laser architectures that exhibit best power-scaling capabilities remains a major challenge.Here,we present a very compact and highly robust method to compress 1.24 ps pulses to 39fs by means of only a single spectral broadening stage which neither requires vacuum parts nor custom-made optics.Our approach is based on the hybridization of the multiplate continuum and.the multipass cell spectral broadening techniques.Their combination leads to significantly higher spectral broadening factors in bulk material than what has been reported from either method alone.Moreover,our approach efficiently suppresses adverse features of single-pass bulk spectral broadening.We use a burst-mode Yb:YAG laser emitting pulses with 80 MW peak power that are enhanced to more than 1 GW after postcompression.With only 0.19%rms pulse-to-pulse energy fluctuations,the technique exhibits excellent stability.Furthermore,we have measured state-of-the-art spectral-spatial homogeneity and good beam quality of M^(2)=1.2 up to a spectral broadening factor of 30.Due to the method's simplicity,compactness,and scalability,it is highly attractive for turning a picosecond laser into an ultrafast light source that generates pulses of only a few tens of femtoseconds duration.
