Hello.
We have Ti:sapphire ultrafast laser. In oscillator, the bandwidth of the Kerr-lensed mode-locked (phase-locked) laser is exceeding 60 or 70 nm. After passing through two amplification stages the bandwidth is significantly reduced to about half or even lower. As we need shorter pulse duration as much as possible, It is very great to implement some technique to reduce the spectral narrowing during amplification. One method I've heard is that there is special filter making spectrum flat before entering amplification. Could you give me some idea?
Hello Donggyu,
Have a look at this article by Durfee et al.
C. G. Durfee, S. Bera, A. J. Sabbah, J. A. Squier, and M. Ellison, “Spectral shaping filter for broadband amplifiers,” Optics Communications, vol. 263, no. 2, pp. 256–260, Jul. 2006.
http://www.sciencedirect.com/science/article/pii/S0030401806000708
Using these filters and techniques, I have been able to produce 4mJ pulses from a Ti:sapphire regen.
Best regards,
Alan
Oh god! Thanks! papers Alan and Tariq suggested for me is exactly want I really want! So much thank you!!!!!
For those stuck behind a pay wall: the 1996 Barty paper is a great paper describing three individual additions into a regenerative amplifier that can be used for spectral shaping/gain narrowing compensation: a thin etalon, a spatial mask at the Fourier plane of a 4-f-zero-dispersion stretcher, and a birefringent filter.
Other options for gain narrowing alleviation include using acousto-optics (acousto-optic programmable dispersive filter (AOPDF)/acousto-optic programmable gain control filter (AOPGCF)) or gain-narrowing filters/gain-flattening mirrors.
In my group, we have used self-phase modulation in a hollow-core fiber to regain the spectrum lost to gain narrowing. Many groups immediately compress such a spectrum to
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