Temporal evolution of soft x-ray pulse emitted from aluminum plasma produced by a pair of Ti:sapphire laser pulses

Abstract

The temporal and spectral evolution of soft x-ray pulses (40–100 Å) emitted from Al plasma produced by a pair of femtosecond Ti:sapphire laser pulses at normal incidence was studied. Both the soft x-ray emission and the pulse duration increased with increase in the scale length of the preformed plasma. Prepulse enhanced soft x-ray emission about 100 times with a pulse duration of 100–130 ps. A spectrally resolved time history revealed that the emission at shorter wavelengths started and decayed relatively more quickly, and emissions at longer wavelengths built up and decayed more slowly.

Role of surface roughness in hard-x-ray emission from femtosecond-laser-produced copper plasmas

“…Pre-plasma formation has been investigated in detail as one of the prominent ways of improving the x-ray yields. While significant enhancement in the emission is noticed, the x-ray pulse duration tends to become longer in such cases [11,12]. There is increasing interest on the role of modulation/roughness of the surface in increasing the coupling of the input light into the plasma, which results in an enhancement in the x-ray yield.…”

Short-Pulse Laser-Produced Plasmas

“…Preplasma formation has been investigated in detail as one of the prominent ways of improving the x-ray yields [29]. While significant enhancement in the emission is noticed, it has also been shown that the x-ray pulse duration tends to become longer in such cases [30,31]. The role of modulation/roughness of the surface in increasing the coupling of the input light into the plasma, which results in an enhancement in the x-ray yield, has been studied in detail.…”

Strongly enhanced soft x-ray emission at 8 nm from plasma on a neodymium-doped glass surface heated by femtosecond laser pulses

“…[3][4][5][6][7][8] We have observed an enhancement of 100 times in soft x-ray emission using this scheme. 6,8,9 The low-density plasma created by the prepulse not only increased the light absorption, but also broadened the pulse duration in the soft x-ray region to more than 100 ps. 8,9 Another way to increase the light absorption is the use of structured target such as grating and porous.…”

“…6,8,9 The low-density plasma created by the prepulse not only increased the light absorption, but also broadened the pulse duration in the soft x-ray region to more than 100 ps. 8,9 Another way to increase the light absorption is the use of structured target such as grating and porous. [10][11][12] Recently, quartz and other insulators were reported to show higher absorption of ultrashort laser pulses at low laser intensities ͑10 13 -10 15 W/cm 2 at 400 nm͒.…”

“…The time-resolved spectrograph consisted of a toroidal mirror with a 300 mm focal length, a transmission grating with a 200 nm period, and an x-ray streak camera ͑Hamamatsu C4547͒ which had a CsI photocathode. 9 This system can observe time history of soft x-ray emissions in the range 4-10 nm with temporal and spectral resolutions of 3 ps and 0.3 nm, respectively.…”