Mid-Infrared Frequency Generation via Intermodal Difference Frequency Generation in AlGaAs-On-Insulator Waveguides

We investigate theoretically mid-infrared (MIR) generation via difference frequency generation in multimode AlGaAs-on insulator (AlGaAs-OI) waveguides. The large refractive index difference between the AlGaAs core and the silica cladding shrinks the modes size down to the sub-μm2 scale, and, together with AlGaAs strong second-order nonlinear polarization, empowers strong nonlinear effects. As a result, efficient MIR generation is obtained in few-cm long waveguides with sub-μm2 transverse section, where higher order modes are exploited to achieve the phase-matching condition. These observations suggest that multimode AlGaAs-OI waveguides could represent a novel promising platform for on-chip, compact MIR sources.

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Phase-matching condition for THz wave generation via difference frequency generation using InxGa1-xSe mixed crystals

Optics Express ◽

10.1364/oe.393948 ◽

2020 ◽

Vol 28 (14) ◽

pp. 20888

Author(s):

Yohei Sato ◽

Mayu Nakajima ◽

Chao Tang ◽

Katsuya Watanabe ◽

Tadao Tanabe ◽

...

Keyword(s):

Difference Frequency Generation ◽

Matching Condition ◽

Wave Generation ◽

Mixed Crystals ◽

Difference Frequency ◽

Phase Matching ◽

Thz Wave ◽

Frequency Generation ◽

Phase Matching Condition

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Widely tunable terahertz-wave generation from planar GaP waveguides via difference frequency generation under collinear phase-matching condition

Japanese Journal of Applied Physics ◽

10.7567/jjap.53.102203 ◽

2014 ◽

Vol 53 (10) ◽

pp. 102203 ◽

Cited By ~ 1

Author(s):

Kyosuke Saito ◽

Tadao Tanabe ◽

Yutaka Oyama

Keyword(s):

Difference Frequency Generation ◽

Matching Condition ◽

Terahertz Wave ◽

Wave Generation ◽

Difference Frequency ◽

Phase Matching ◽

Frequency Generation ◽

Phase Matching Condition

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Efficient idler broadening via oppositely dual-chirped difference frequency generation

High Power Laser Science and Engineering ◽

10.1017/hpl.2020.24 ◽

2020 ◽

Vol 8 ◽

Author(s):

Haizhe Zhong ◽

Bin Hu ◽

Saisai Hu ◽

Shengying Dai ◽

Ying Li ◽

...

Keyword(s):

Frequency Conversion ◽

Laser System ◽

Difference Frequency Generation ◽

Matching Condition ◽

Difference Frequency ◽

Phase Matching ◽

Periodically Poled ◽

Frequency Generation ◽

Phase Matching Condition ◽

Gain Characteristic

Dual-chirped difference frequency generation (DFG) is an advantageous technique for generating the broadband mid-infrared (IR) idler wave, which is inaccessible by a population-inversion-based laser system. In principle, the generated idler wave may even suffer a spectrum broadening compared with the driving pulsed lasers if the pump and signal waves are oppositely chirped. However, broadband phase-matching is always the determining factor for the resulting efficiency and the bandwidth of the generated idler wave. In this study, specific to an oppositely dual-chirped DFG scheme, we derive the precondition to realize broadband frequency conversion, wherein a negative $(1/\unicode[STIX]{x1D710}_{p}-1/\unicode[STIX]{x1D710}_{i})/(1/\unicode[STIX]{x1D710}_{s}-1/\unicode[STIX]{x1D710}_{i})$ , in terms of the correlation coefficient of the group velocity ( $\unicode[STIX]{x1D70E}$ ), is necessary. However, most birefringence bulk crystals can only provide the required material dispersions in limited spectral regions. We show that the periodically poled lithium niobate crystal that satisfies an inactive Type-II (eo-o) quasi-phase-matching condition has a stable negative $\unicode[STIX]{x1D70E}$ and exerts the expected broadband gain characteristic across an ultra-broad idler spectral region $(1.7{-}4.0~\unicode[STIX]{x03BC}\text{m})$ . Finally, we propose and numerically verify a promising DFG configuration to construct a tunable mid-IR spectrum broader based on the broadband phase-matched oppositely dual-chirped DFG scheme.

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

Electronics ◽

10.3390/electronics10030336 ◽

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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