Sub-300 fs, 0.5 mJ Pulse at 1kHz from Ho:YLF Amplifier and Kagome Pulse Compression (original) (raw)
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Optics letters, 2015
Compression of 250-fs, 1-μJ pulses from a KLM Yb:YAG thin-disk oscillator down to 9.1 fs is demonstrated. A kagomé-PCF with a 36-μm core-diameter is used with a pressure gradient from 0 to 40 bar of krypton. Compression to 22 fs is achieved by 1200 fs<sup>2</sup> group-delay-dispersion provided by chirped mirrors. By coupling the output into a second kagomé-PCF with a pressure gradient from 0 to 25 bar of argon, octave spanning spectral broadening via the soliton-effect is observed at 18-W average output power. Self-compression to 9.1 fs is measured, with compressibility to 5 fs predicted. Also observed is strong emission in the visible via dispersive wave generation, amounting to 4% of the total output power.
Optics letters, 2014
We present nonlinear pulse compression of a high-power SESAM-modelocked thin-disk laser (TDL) using an Ar-filled hypocycloid-core kagome hollow-core photonic crystal fiber (HC-PCF). The output of the modelocked Yb:YAG TDL with 127 W average power, a pulse repetition rate of 7 MHz, and a pulse duration of 740 fs was spectrally broadened 16-fold while propagating in a kagome HC-PCF containing 13 bar of static argon gas. Subsequent compression tests performed using 8.4% of the full available power resulted in a pulse duration as short as 88 fs using the spectrally broadened output from the fiber. Compressing the full transmitted power through the fiber (118 W) could lead to a compressed output of >100 W of average power and >100 MW of peak power with an average power compression efficiency of 88%. This simple laser system with only one ultrafast laser oscillator and a simple single-pass fiber pulse compressor, generating both high peak power >100 MW and sub-100-fs pulses at...
Generation of 50 fs, 50 mJ pulses at 1 kHzusing hollow-fiber pulse compression
Optics Letters, 2010
We demonstrate methods to increase the energy incident on hollow fibers for spectral broadening by self-phase modulation. We used chirped pulses for spectral broadening, lowering the optical intensity to avoid ionization of the gaseous medium. We also used helium as a nonlinear medium and demonstrated the generation of 5:0 fs, 5:0 mJ pulses at a repetition rate of 1 kHz using a pressure gradient hollow-fiber pulse compressor.
2012
We report on the recent design and fabrication of kagome-type hollow-core photonic crystal fibers for the purpose of high-power ultrashort pulse transportation. The fabricated seven-cell three-ring hypocycloid-shaped large core fiber exhibits an up-to-date lowest attenuation (among all kagome fibers) of 40 dB ∕ km over a broadband transmission centered at 1500 nm. We show that the large core size, low attenuation, broadband transmission, single-mode guidance, and low dispersion make it an ideal host for high-power laser beam transportation. By filling the fiber with helium gas, a 74 μJ, 850 fs, and 40 kHz repetition rate ultrashort pulse at 1550 nm has been faithfully delivered at the fiber output with little propagation pulse distortion. Compression of a 105 μJ laser pulse from 850 fs down to 300 fs has been achieved by operating the fiber in ambient air.
European Physical Journal-special Topics, 2009
The compression of laser pulses at 527 nm, 250 fs long, down to 30 fs is reported. The laser pulses, originated from a frequency-doubled, mode-locked Nd:glass laser, were compressed by a 0.7-m-long, 150-μ m-bore-diameter argon-filled hollow fiber and a pair of SF10 prisms with a final energy of 160 μJ. These are the shortest, high energy pulses ever produced by direct pulse compression at the central wavelength of 527 nm. The spectral broadening of the pulses propagating inside the hollow fiber was experimentally examined for various filling-gas pressures and input pulse energies. The physical limitations of the hollow-fiber pulse compression technique applied in the visible range are also studied. An application to laser ablation of Ni target is performed. Metal nanoparticles are obtained both with the 250-fs and with the 30-fs pulse.
High harmonic generation in a gas-filled hollow-core photonic crystal fiber
Applied Physics B-lasers and Optics, 2009
High harmonic generation (HHG) of intense infrared laser radiation (Ferray et al., J. Phys. B: At. Mol. Opt. Phys. 21:L31, 1988; McPherson et al., J. Opt. Soc. Am. B 4:595, 1987) enables coherent vacuum-UV (VUV) to soft-X-ray sources. In the usual setup, energetic femtosecond laser pulses are strongly focused into a gas jet, restricting the interaction length to the Rayleigh range of the focus. The average photon flux is limited by the low conversion efficiency and the low average power of the complex laser amplifier systems (Keller, Nature 424:831, 2003; Südmeyer et al., Nat. Photonics 2:599, 2008; Röser et al., Opt. Lett. 30:2754, 2005; Eidam et al., IEEE J. Sel. Top. Quantum Electron. 15:187, 2009) which typically operate at kilohertz repetition rates. This represents a severe limitation for many experiments using the harmonic radiation in fields such as metrology or high-resolution imaging. Driving HHG with novel high-power diode-pumped multi-megahertz laser systems has the potential to significantly increase the average photon flux. However, the higher average power comes at the expense of lower pulse energies because the repetition rate is increased by more than a thousand times, and efficient HHG is not possible in the usual geometry. So far, two promising techniques for HHG at lower pulse energies were developed: external build-up cavities (Gohle et al., Nature 436:234, 2005; Jones et al., Phys. Rev. Lett. 94:193, 2005) and resonant field enhancement in nanostructured targets (Kim et al., Nature 453:757, 2008). Here we present a third technique, which has advantages in terms of ease of HHG light extraction, transverse beam quality, and the possibility to substantially increase conversion efficiency by phase-matching (Paul et al., Nature 421:51, 2003; Ren et al., Opt. Express 16:17052, 2008; Serebryannikov et al., Phys. Rev. E (Stat. Nonlinear Soft Matter Phys.) 70:66611, 2004; Serebryannikov et al., Opt. Lett. 33:977, 2008; Zhang et al., Nat. Phys. 3:270, 2007). The interaction between the laser pulses and the gas occurs in a Kagome-type Hollow-Core Photonic Crystal Fiber (HC-PCF) (Benabid et al., Science 298:399, 2002), which reduces the detection threshold for HHG to only 200 nJ. This novel type of fiber guides nearly all of the light in the hollow core (Couny et al., Science 318:1118, 2007), preventing damage even at intensities required for HHG. Our fiber guided 30-fs pulses with a pulse energy of more than 10 μJ, which is more than five times higher than for any other photonic crystal fiber (Hensley et al., Conference on Lasers and Electro-Optics (CLEO), IEEE Press, New York, 2008).