Flattop wideband wavelength converters based on cascaded sum and difference-frequency generation using step-chirped gratings

2011 ◽  
Author(s):  
Amirhossein Tehranchi ◽  
Raman Kashyap
Keyword(s):  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Wavelength Converters ◽  
Chirped Gratings ◽  
Frequency Generation

Investigation of Broadband Wavelength Conversion Based on Cascaded Second-Harmonic Generation and Difference Frequency Generation

2015 ◽  
Vol 738-739 ◽  
pp. 759-762
Author(s):  
Jin Song Guo ◽  
Zhao Xia Wang ◽  
Hai Dong Wu ◽  
Yun Wen Wu
Keyword(s):  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Wavelength Conversion ◽  
Second Harmonic ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Double Pass ◽  
Single Pass ◽  
Chirped Gratings ◽  
Frequency Generation

Step-chirped gratings is utilized to broaden the bandwidth of wavelength conversion based on single-pass/ double-pass cascaded second harmonic generation and difference frequency generation. By adding the step-chirped gratings number and optimizing the poling period, broad conversion bandwidth and flat response can be obtained simultaneously. The bandwidth of 4-cm-long waveguide with 6-section chirped gratings are 169 nm for single-pass scheme and 164 nm for the double-pass one, which are 98 nm and 101 nm larger than those of uniform gratings, respectively. Furthermore, comparison between step-chirped gratings and equal-segmented gratings is carried out.

scholarly journals Spectroscopic Imaging with an Ultra-Broadband (1–4 THz) Compact Terahertz Difference-Frequency Generation Source

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 336
Author(s):  
Atsushi Nakanishi ◽  
Shohei Hayashi ◽  
Hiroshi Satozono ◽  
Kazuue Fujita
Keyword(s):  
Imaging Technique ◽  
Spectroscopic Imaging ◽  
Difference Frequency Generation ◽  
Difference Frequency ◽  
Quality Monitoring ◽  
Terahertz Emission ◽  
Mid Infrared ◽  
Quantum Cascade ◽  
Frequency Generation ◽  
Multi Mode

We demonstrate spectroscopic imaging using a compact ultra-broadband terahertz semiconductor source with a high-power, mid-infrared quantum cascade laser. The electrically pumped monolithic source is based on intra-cavity difference-frequency generation and can be designed to achieve an ultra-broadband multi-mode terahertz emission spectrum extending from 1–4 THz without any external optical setup. Spectroscopic imaging was performed with three frequency bands, 2.0 THz, 2.5 THz and 3.0 THz, and as a result, this imaging technique clearly identified three different tablet components (polyethylene, D-histidine and DL-histidine). This method may be highly suitable for quality monitoring of pharmaceutical materials.

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