waveform-controlled-IR-sources
FP 1: Femtopower Pro C-E Phase (Femtolasers GmbH), Ti:sapphire MOPA system delivering carrier-envelope-phase(CEP)-stabilized NIR laser pulses with a duration of 25 fs and pulse energy of 0.8 mJ at a repetition rate of 3 kHz. With a home-built hollow-fibre/chirped-mirror compressor these pulses are compressed to less than 4 femtoseconds at a pulse energy of ~0.25 mJ.
contact: E. Goulielmakis
FP 2: Customized version of Femtopower Pro C-E Phase, providing CEP-stabilized pulses with increased bandwidth (~70 nm), shorter pulse duration (~ 20 fs) at enhanced pulse energies (~1.1 mJ). The seed source (Rainbow) has been tuned to provide a ~70MHz pulse train with ~3 nJ pulses, with spectral bandwidth from ~600 nm to ~1050 nm. Spectral components above 1000 nm are used to seed the pump source for LWS-1. The spectral region between 700 nm to 900 nm is used – after being stretched to ~1 ps in a glass block – to seed the multipass amplifier, yielding ~1.3 mJ pulses. These are compressed to ~20 fs in a hybrid (prism/chirped-mirror) compressor. Some 10% of this output is used for generating the broadband mid-IR seed for LWS-1. The remaining 90% is used to seed a hollow-core fibre filled with neon gas for subsequent spectral broadening. Due to the enhanced input bandwidth, and shorter pulse duration, the output spectrum from the HCF spans more than 1.5 octaves allowing for direct non-invasive access to the CE-phase of the amplified pulse, so that it can be adjusted if it has drifted during amplification. Finally, using chirped mirrors, designed to accommodate such broad bandwidth, these waveform controlled “white” pulses can be compressed to ~3.5 fs with ~0.4 mJ pulse energy, leading to a peak power of ~0.1 TW.
contact: M. Schultze
FP 3: Two-stage, Ti:sapphire MOPA system incorporating pressuregradient spectral broadening in hollow-core fibre and compression in chirped mirrors (CMs). Oscillator: 78MHz, sub-7fs (Rainbow). Stretcher: Grism pair designed to negatively stretch the pulses to ~28 ps and control both 2nd and 3rd order dispersion. Amplifier: two-stage down-chirped pulse amplification. The first stage incorporates a Femtopower Pro CE-Phase to deliver pulses of 1 mJ, ~25 ps at 4 kHz. The second stage is a 4-pass cryogenically-cooled booster (Thales Laser) for further amplification to ~4 mJ, ~25 ps. Compressor: hybrid compressor of glass blocks and positive-dispersion CMs resulting in 3.5-mJ, 20-fs pulses. Hollow-fibre/CM compressor: SPM broadens the spectrum of the 20-fs pulses in a rare-gas-filled pressure-gradient hollow-core fibre to octave span. CEP stabilization: with PPLN-based monolithic phase detector (Femtolasers) and f-to-2f interferometer using octave-spanning spectrum directly from the hollow fibre via piezo-controlled adjustment of grism separation. CEP measurement: out-of-loop interferometer. Output: 1.5 mJ, sub-5 fs, 4 kHz pulses with controlled waveform.
contact: A. Cavalieri, E. Goulielmakis, M. Schultze
contact: E. Goulielmakis
FP 2: Customized version of Femtopower Pro C-E Phase, providing CEP-stabilized pulses with increased bandwidth (~70 nm), shorter pulse duration (~ 20 fs) at enhanced pulse energies (~1.1 mJ). The seed source (Rainbow) has been tuned to provide a ~70MHz pulse train with ~3 nJ pulses, with spectral bandwidth from ~600 nm to ~1050 nm. Spectral components above 1000 nm are used to seed the pump source for LWS-1. The spectral region between 700 nm to 900 nm is used – after being stretched to ~1 ps in a glass block – to seed the multipass amplifier, yielding ~1.3 mJ pulses. These are compressed to ~20 fs in a hybrid (prism/chirped-mirror) compressor. Some 10% of this output is used for generating the broadband mid-IR seed for LWS-1. The remaining 90% is used to seed a hollow-core fibre filled with neon gas for subsequent spectral broadening. Due to the enhanced input bandwidth, and shorter pulse duration, the output spectrum from the HCF spans more than 1.5 octaves allowing for direct non-invasive access to the CE-phase of the amplified pulse, so that it can be adjusted if it has drifted during amplification. Finally, using chirped mirrors, designed to accommodate such broad bandwidth, these waveform controlled “white” pulses can be compressed to ~3.5 fs with ~0.4 mJ pulse energy, leading to a peak power of ~0.1 TW.
contact: M. Schultze
FP 3: Two-stage, Ti:sapphire MOPA system incorporating pressuregradient spectral broadening in hollow-core fibre and compression in chirped mirrors (CMs). Oscillator: 78MHz, sub-7fs (Rainbow). Stretcher: Grism pair designed to negatively stretch the pulses to ~28 ps and control both 2nd and 3rd order dispersion. Amplifier: two-stage down-chirped pulse amplification. The first stage incorporates a Femtopower Pro CE-Phase to deliver pulses of 1 mJ, ~25 ps at 4 kHz. The second stage is a 4-pass cryogenically-cooled booster (Thales Laser) for further amplification to ~4 mJ, ~25 ps. Compressor: hybrid compressor of glass blocks and positive-dispersion CMs resulting in 3.5-mJ, 20-fs pulses. Hollow-fibre/CM compressor: SPM broadens the spectrum of the 20-fs pulses in a rare-gas-filled pressure-gradient hollow-core fibre to octave span. CEP stabilization: with PPLN-based monolithic phase detector (Femtolasers) and f-to-2f interferometer using octave-spanning spectrum directly from the hollow fibre via piezo-controlled adjustment of grism separation. CEP measurement: out-of-loop interferometer. Output: 1.5 mJ, sub-5 fs, 4 kHz pulses with controlled waveform.
contact: A. Cavalieri, E. Goulielmakis
, M. Schultze
More reading:
Fig. 1. Femtopower laser. (© thn)