Journal Articles (peer reviewed)

1. ``Energy and information flow in superlensing '' [PDF]
   E. Fourkal, I. Velchev, and A. Smolyakov
   Phys. Rev. A 79 (3), 033846 (2009).

2. ``Laser-to-proton energy transfer efficiency in laser-plasma interactions'' [PDF]
   E. Fourkal, I. Velchev, and C.-M. Ma
   J. Plasma Phys. 75, 235-250 (2009).

3. ``Decoupling and asymmetric coupling in triple-core photonic crystal fibers'' [PDF]
   Y. Yan, J. Toulouse, I. Velchev, and S. Rotkin
   J. Opt. Soc. Am B, 25 (9), 1488-1495 (2008).

4. ``Shielding design for a laser-accelerated proton therapy system'' [PDF]
   J. Fan, W. Luo, E. Fourkal, T. Lin, J. Li, I. Velchev, N. E. Ipe, and C.-M. Ma
   Physics in Medicine and Biology, 52 (13), 3913-3930 (2007).

5. ``Laser induced Coulomb mirror effect: applications for proton acceleration'' [PDF]
   I. Velchev, E. Fourkal, and C.-M. Ma
   Physics of Plasmas 14 (3) 33106 (2007).

6. ``Energy optimization procedure for treatment planning with laser-accelerated protons'' [PDF]
   E. Fourkal, I. Velchev, J. Fan, W. Luo, and C.-M. Ma
   Medical Physics 34 (2), 577-584 (2007).

7. ``Resonant transparency of opaque materials'' [PDF]
   E. Fourkal, I. Velchev, and A. Smolyakov
   Physics Letters A 361, 277-282 (2007).

8. ``Creation of tailored features by laser heating of Nd$_{0.2}$La$_{0.8}$BGeO$_5$ glass'' [PDF]
   P. Gupta, H. Jain, D.B. Williams, J. Toulouse, and I. Veltchev
   Optical Materials 29 (4), 355-359 (2006).

9. ``Development of a laser-driven proton accelerator for cancer therapy'' [PDF]
   C.-M. Ma, I. Velchev, E. Fourkal, J. S. Li, W. Luo, J. Fan, and A. Pollack
   Laser Physics 16 (4), 1-8 (2006).

10. ``Evanescent wave interference and the total transparency of a warm high-density plasma slab'' [PDF]
    E. Fourkal, I. Velchev, A. Smolyakov, and C.-M. Ma
    Physics of Plasmas 13 (9), 092113 (2006).

11. ``Coulomb explosion effect and the maximum energy of protons accelerated by high-power lasers'' [PDF]
    E. Fourkal, I. Velchev, and C.-M. Ma
    Physical Review E 71 (3), 036412 (2005).

12. ``Statistical properties of the Stokes signal in stimulated Brillouin scattering pulse compressors'' [PDF]
    I. Velchev and W. Ubachs
    Physical Review A 71 (4), 043810 (2005).

13. ``Two-beam modulation instability in noninstantaneous nonlinear media'' [PDF]
    I. Velchev, R. Pattnaik, and J. Toulouse
    Physical Review Letters 91, 093905 (2003).

14. ``Fourier analysis of the spectral properties of multi-mode laser radiation'' [PDF]
    I. Velchev and J. Toulouse
    The American Journal of Physics 71 (3), 269-272 (2003).

15. ``A novel narrow-band wavelength-tunable laser system delivering high-energy 300 ps pulses in the near-infrared'' [PDF]
    F. Brandi, I. Velchev, D. Neshev, W. Hogervorst, and W. Ubachs
    Review of Scientific Instruments 74 (1), 32-37 (2003).

16. ``Higher order stimulated Brillouin scattering with non-diffracting beams'' [PDF]
    I. Velchev and W. Ubachs
    Optics Letters 26 (8), 530-532 (2001).

17. ``Vacuum-ultraviolet spectroscopy of Xe: Hyperfine splittings, isotope shifts, and isotope-dependent ionization energies'' [PDF]
    F. Brandi, I. Velchev, W. Hogervorst, and W. Ubachs
    Physical Review A 64 (3), 032505 (2001).

18. ``Lifetime measurements on the $c'_{4}$ $^{1}\Sigma_{u}^{+}$, v=0, 1, and 2 states of molecular nitrogen'' [PDF]
    W. Ubachs, R. Lang, I. Velchev, W. -U. L. Tchang-Brillet, A. Johansson, Z. S. Li, V. Lokhnygin, and C. -G. Wahlstrom
    Chemical Physics 270 (1), 215-225 (2001).

19. ``Isotope dependent predissociation in the $C$ $^{1}\Sigma^{+}$, v=0 and v=1 states in CO'' [PDF]
    P. Cacciani, F. Brandi, I. Velchev, C. Lynga, C. -G. Wahlstrom, and W. Ubachs
    The European Physics Journal D15 (1), 47-56 (2001).

20. ``Predissociation in the $E$ $^{1}\Pi$ ,v=1 state of the six natural isotopomers of CO'' [PDF]
    W. Ubachs, I. Velchev, and P. Cacciani
    Journal of Chemical Physics 113 (2), 547-560 (2000).

21. ``Predissociation of $b$ $^{1}{\Pi}_{u}$ ,v (v=1,4,5,6) levels of N$_2$'' [PDF]
    W. Ubachs, I. Velchev, and A. de Lange
    Journal of Chemical Physics 112 (13), 5711-5716 (2000).

22. ``Pulse compression to the sub-phonon lifetime region by half-cycle gain in transient stimulated Brillouin scattering'' [PDF]
    I. Velchev, D. Neshev, W. Hogervorst, W. Ubachs
    IEEE Journal of Quantum Electronics QE-35 (12), 1812-1816 (1999).

23. ``Precision VUV spectroscopy of argon I at 105 nm'' [PDF]
    I. Velchev, W. Hogervorst, W. Ubachs
    Journal of Physics B32 (17), L511-L516 (1999).

24. ``Steering of one-dimensional odd dark beams of finite length'' [PDF]
    A. Dreischuh, G. G. Paulus, F. Zacher, I. Velchev
    Applied Physics B69 (2), 113-117 (1999).

25. ``SBS pulse compression to 200 ps in a compact single-cell setup'' [PDF]
    D. Neshev, I. Velchev, W. A. Majewski, W. Hogervorst, and W. Ubachs
    Applied Physics B68 (4), 671-675 (1999).

26. ``A dense grid of reference Iodine lines for optical frequency calibration in the range 571-596nm'' [PDF]
    I. Velchev, R. van Dierendonck, W. Hogervorst, and W. Ubachs
    Journal of Molecular Spectroscopy 187 (1), 21-27 (1998).

27. ``Multiple-charged optical vortex solitons in bulk Kerr media'' [PDF]
    I. Velchev, A. Dreischuh, D, Neshev, S. Dinev
    Optics Communications 140 (1-3), 77-82 (1997).

28. ``Interaction of optical vortex solitons superimposed on different background beams'' [PDF]
    I. Velchev, A. Dreischuh, D. Neshev, and S. Dinev
    Optics Communications 130 (4-6), 385-392 (1996).

29. ``Phase measurements of ring dark solitons'' [PDF]
    A. Dreischuh, W. Fliesser, I. Velchev, S. Dinev, and L. Windholz
    Applied Physics B62 (2), 139-142 (1996).

30. ``Generation and evolution of two-dimensional dark spatial solitons'' [PDF]
    S. Baluschev, A. Dreischuh, I. Velchev, S. Dinev, and O. Marazov
    Physical Review E 52 (5), 5517-5523 (1995).

31. ``Odd and even two-dimensional dark spatial solitons'' [PDF]
    S. Baluschev, A. Dreischuh, I. Velchev, S. Dinev, and O. Marazov
    Applied Physics B61 (1), 121-124 (1995).