Comparative theory of walkoff-limited type-II versus type-I second harmonic generation with gaussian beams

Research output: Contribution to journalArticle

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Abstract

Starting from a unified treatment for type-I and type-II second harmonic generation (SHG) under the undepleted pump assumption based on the heuristic theory, we compare the effect of walkoff on both types of phase-matching (PM). We show that the beam walkoff between the pump polarization waves in type-II interaction may be regarded as an additional absorption in a type-I interaction experiencing the same walkoff angle. Power saturation is reached at about 2.3 times the aperture length which corresponds to the coherence length. Unlike for type-I SHG, the criterion of optimum focusing becomes meaningless in type-II coupling as the walkoff angle or the crystal length increase. The optimum SHG power or beam shape are then well described by the parallel beam limiting case. Furthermore, it appears that type-II angular far-field intensity distribution remains quasi gaussian whatever the focusing: diffractional effects such as sharp-edged or fringed transverse pattern observed in type-I SH profile under strong focusing do not appear.

Original languageEnglish
Pages (from-to)427-440
Number of pages14
JournalOptics Communications
Volume81
Issue number6
DOIs
Publication statusPublished - Mar 15 1991
Externally publishedYes

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Gaussian beams
Harmonic generation
harmonic generations
Pumps
pumps
polarization (waves)
Phase matching
phase matching
far fields
apertures
interactions
Polarization
saturation
Crystals
profiles
crystals

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

Cite this

Comparative theory of walkoff-limited type-II versus type-I second harmonic generation with gaussian beams. / Zondy, Jean Jacques.

In: Optics Communications, Vol. 81, No. 6, 15.03.1991, p. 427-440.

Research output: Contribution to journalArticle

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