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Forward and backward terahertz-wave difference-frequency generations from periodically poled lithium niobate
1Institute of Photonics Technologies, Department of Electrical Engineering, National Tsing-hua University, Hsinchu 30013, Taiwan.
Optics Express
|June 12, 2008
Summary
This study demonstrates terahertz-wave generation using periodically poled lithium niobate (PPLN) crystals. The research precisely determined the refractive index of lithium niobate in the terahertz range through difference frequency generation.
Area of Science:
- Optics and Photonics
- Materials Science
Background:
- Terahertz (THz) wave generation is crucial for various spectroscopic and imaging applications.
- Periodically poled lithium niobate (PPLN) is a versatile nonlinear optical material for frequency conversion.
Purpose of the Study:
- To report efficient terahertz-wave generation using a multi-grating PPLN crystal.
- To precisely determine the extraordinary refractive index of lithium niobate in the THz range.
Main Methods:
- Utilized forward and backward difference frequency generation (DFG) in a 3.2-cm long multi-grating PPLN crystal.
- Employed a PPLN crystal with a grating period varying from 63 to 70 microm in 1-microm increments.
- Deduced the refractive index from the quasi-phase-matching (QPM) condition.
Main Results:
- Achieved terahertz-wave generation in the wavelength ranges of 190–210 microm and 457–507 microm.
- Precisely determined the extraordinary refractive index of lithium niobate in the THz-wave range.
Conclusions:
- Demonstrated the effectiveness of multi-grating PPLN for broadband THz-wave generation.
- Validated the quasi-phase-matching condition for accurate optical property determination.
