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

doi:10.1109/JLT.2009.2022340

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 journal › Article › peer-review

17 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 language	English
Pages (from-to)	3057-3061
Number of pages	5
Journal	Journal of Lightwave Technology
Volume	27
Issue number	15
DOIs	https://doi.org/10.1109/JLT.2009.2022340
Publication status	Published - 2009 Aug 1
Externally published	Yes

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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10.1109/JLT.2009.2022340

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

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.",

keywords = "Continuous-wave (CW), Difference frequency generation (DFG), GaP, Phase matching, Terahertz (THz)",

author = "Srinivasa Ragam and Tadao Tanabe and Kyosuke Saito and Yutaka Oyama and Nishizawa, {Jun Ichi}",

note = "Funding Information: Manuscript received December 18, 2008; revised April 07, 2009. First published May 05, 2009; current version published July 06, 2009. This work was supported in part by the Tohoku University Global Centre of Excellence (GCOE) program and in part by the Toyota Research Grant Program.",

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doi = "10.1109/JLT.2009.2022340",

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AU - Ragam, Srinivasa

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AU - Oyama, Yutaka

AU - Nishizawa, Jun Ichi

N1 - Funding Information: Manuscript received December 18, 2008; revised April 07, 2009. First published May 05, 2009; current version published July 06, 2009. This work was supported in part by the Tohoku University Global Centre of Excellence (GCOE) program and in part by the Toyota Research Grant Program.

PY - 2009/8/1

Y1 - 2009/8/1

N2 - 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.

AB - 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.

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KW - Phase matching

KW - Terahertz (THz)

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

Abstract

Keywords

ASJC Scopus subject areas

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