MODELING HARMONIC-GENERATION BY A ZERO-RANGE POTENTIAL

被引:271
作者
BECKER, W [1 ]
LONG, S [1 ]
MCIVER, JK [1 ]
机构
[1] UNIV NEW MEXICO, ALBUQUERQUE, NM 87131 USA
来源
PHYSICAL REVIEW A | 1994年 / 50卷 / 02期
关键词
D O I
10.1103/PhysRevA.50.1540
中图分类号
O43 [光学];
学科分类号
070207 ; 0803 ;
摘要
High-order harmonic emission by one electron in a laser field bound to a zero-range potential is extensively discussed. The model yields an expression for the emission rates in the form of a one-dimensional integral that has to be calculated numerically. The solution is based on the quasienergy wave function of the ground state. The approach is very significantly facilitated by suppressing the harmonic components of the wave function at the position of the zero-range potential. This approximation is found to be very accurate except for the third harmonic. In spite of the simplicity of the model, the harmonic spectrum exhibits a very involved structure, occasional harmonics being strongly suppressed, with cusps and spikes for certain evenly spaced intensities. The latter are due to channel closings for the same intensities in above-threshold ionization. The harmonics near and beyond the cutoff of the plateau are amenable to a completely analytical approximation. This approximation shows how the classical model of Krause, Schafer, and Kulander [Phys. Rev. Lett. 68, 3535 (1992)] is embedded in a fully-quantum-mechanical description. Results are also given for the harmonic production rates in an elliptically polarized laser field; they display fair agreement with recent measurements. The model should adequately describe harmonic emission by negative ions with just one bound s state. Moreover, it also gives a fair description of harmonic emission by an atom, particularly if the ground-state energy of the zero-range potential is adjusted not to the binding energy of the atom, but rather to the energy difference between the ground state and the first excited state. The reason why this is appropriate is found in lowest-order perturbation theory, which sheds some light on the physical origin of the plateau.
引用
收藏
页码:1540 / 1560
页数:21
相关论文
共 76 条
[31]   COLLECTIVE EFFECTS IN INTENSE LASER FIELDS [J].
GIAMMANCO, F .
PHYSICAL REVIEW A, 1991, 43 (12) :6939-6952
[32]   DIRECT 9TH HARMONIC CONVERSION OF PICOSECOND LASER-PULSES [J].
GROZEVA, MG ;
METCHKOV, DI ;
MITEV, VM ;
PAVLOV, LI ;
STAMENOV, KV .
OPTICS COMMUNICATIONS, 1977, 23 (01) :77-79
[33]   GENERATION OF HIGH-ORDER HARMONICS FROM INERTIALLY CONFINED MOLECULAR-IONS [J].
IVANOV, MY ;
CORKUM, PB .
PHYSICAL REVIEW A, 1993, 48 (01) :580-590
[34]   NONADIABATIC LANDAU-ZENER TRANSITIONS AND HIGH-HARMONIC GENERATION [J].
KAMINSKI, JZ .
PHYSICS LETTERS A, 1990, 151 (6-7) :308-313
[35]   SUPERDRESSED 2-LEVEL ATOM - VERY HIGH HARMONIC-GENERATION AND MULTIRESONANCES [J].
KAPLAN, AE ;
SHKOLNIKOV, PL .
PHYSICAL REVIEW A, 1994, 49 (02) :1275-1280
[36]   HIGH-ORDER HARMONIC-GENERATION BY ULTRASHORT KRF AND TISAPPHIRE LASERS [J].
KONDO, K ;
SARUKURA, N ;
SAJIKI, K ;
WATANABE, S .
PHYSICAL REVIEW A, 1993, 47 (04) :R2480-R2483
[37]   CALCULATION OF PHOTOEMISSION FROM ATOMS SUBJECT TO INTENSE LASER FIELDS [J].
KRAUSE, JL ;
SCHAFER, KJ ;
KULANDER, KC .
PHYSICAL REVIEW A, 1992, 45 (07) :4998-5010
[38]   HIGH-ORDER HARMONIC-GENERATION FROM ATOMS AND IONS IN THE HIGH-INTENSITY REGIME [J].
KRAUSE, JL ;
SCHAFER, KJ ;
KULANDER, KC .
PHYSICAL REVIEW LETTERS, 1992, 68 (24) :3535-3538
[39]  
KULANDER K, UNPUB
[40]  
Kulander K. C., 1992, ATOMS INTENSE LASER, P247