Enhancement of CW THz wave power under noncollinear phase-matching conditions in difference frequency generation

Srinivasa Ragam, Tadao Tanabe, Kyosuke Saito, Yutaka Oyama, Jun Ichi Nishizawa

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

We investigated methods for improvement of continuous- wave (CW) terahertz (THz) output power by laser diode (LD) pumping in noncollinear phase-matched difference frequency generation (DFG). The effects of interaction length and beam spot size of input lasers (near-IR) in GaP crystals were studied. The THz wave power dependence on various sizes of GaP crystals was investigated and it was observed that an output power of 4 nW was obtained with a 20 mm long GaP crystal at 1.5 THz. Also, the THz wave absorption coefficient was dominant for longer GaP crystals at high frequencies (above 2.5 THz). The THz wave power dependence on beam spot size (1.2 mm-300μm) of near-IR lasers at 1.62 THz was studied, and an improvement of THz wave power being seen with a 500 μm beam spot size, while the beam divergence effect was dominant for beam spot sizes below 500 μm.

Original languageEnglish
Pages (from-to)3057-3061
Number of pages5
JournalJournal of Lightwave Technology
Volume27
Issue number15
DOIs
Publication statusPublished - 2009 Aug 1
Externally publishedYes

Keywords

  • Continuous-wave (CW)
  • Difference frequency generation (DFG)
  • GaP
  • Phase matching
  • Terahertz (THz)

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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