Two-stage nonlinear compression of high-power femtosecond laser pulses

Abstract

Two-stage compression of laser pulses with a power of 250 TW is experimentally realised by broadening their spectrum during self-phase modulation in fused silica and subsequent dispersion compensation upon reflection from chirping mirrors. A five-fold decrease in the duration is demonstrated, from 75 to 15 fs, with a B-integral value of about 5 at each stage. It is possible to avoid small-scale self-focusing due to self-filtering of the laser beam during free propagation in vacuum. With optimal parameters of the dispersive mirror, the pulse can be compressed to a duration of less than 5 fs.

Use of KDP crystal as a Kerr nonlinear medium for compressing PW laser pulses down to 10 fs

“…4. Analogous curves for 5-mm thick and 3-mm thick silica [14,19] are also presented in this figure. Note that these are qualitative data, as a different number of shots was made for different values of α.…”

“…where n 2 and L are, respectively, the nonlinear index of refraction and the thickness of the nonlinear medium, λ 0 =2πс/ω 0 is the central wavelength in vacuum, and I in is the input peak intensity. In particular, in [16] the experiments were performed for the B-integral values up to 19. Large values of B-integral enable a significant increase of the compression ratio.…”

“…Large values of B-integral enable a significant increase of the compression ratio. Also worthy of notice is the demonstration of two-stage compression [19,20] and the theoretical works on detailed numerical modeling [21][22][23] and on expanding the capabilities of the technique aimed at simultaneous contrast enhancement [24][25][26][27][28].…”

“…In the presented work we experimentally studied the compression of an output pulse of the laser PEARL (PEtawatt pARametric Laser [29]) by SMP in a KDP crystal in a wide range of B-integral values from 5 to 19 and compared the obtained results with the ones using silica [14,16,19]…”

Simultaneous Enhancement of Contrast and Power of Femtosecond Laser Pulses by Nonlinear Interferometer

“…The method is called TFC (thin film compression) [11], CafCA (compression after compressor approach) [12], or post-compression [13]. For pulses with energy of tens of Joules [14][15][16], the multiple compression of femtosecond laser pulses was demonstrated with almost no energy loss; for more details, see the review [17].…”