Research Overview
![Chengying Bao](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-04-27_at_12.51.03_PM.max-250x250.png)
Postdoctoral Fellow, Chengying Bao, is a member of a research team that developed a new technique for the generation of mid-IR frequency combs called interleaved difference-frequency generation (iDFG). The results of this study have been summarized in the publication, "Interleaved Difference-Frequency Generation for Microcomb Spectral Densification in the Mid-Infrared". The iDFG technique is a meaningful step towards more compact and possibly chip-based mid-IR gas spectroscopy modules, that can be used in methane emission measurement and chemical threat detection.
Scientific Achievement
We introduce a new technique for the generation of integrable mid-IR frequency combs: interleaved difference-frequency generation (iDFG).
![Experimental scheme towards integrated low repetition rate mid-IR combs using iDFG](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-09-23_at_12.41.09_PM.original.png)
![Experimental scheme towards integrated low repetition rate mid-IR combs using iDFG](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-09-23_at_12.41.09_PM.max-1400x800.png)
Significance and Impact
The new iDFG method for narrow line spacing mid-IR comb generation can be integrated and used in methane emission measurement and chemical threat detection.
![Generation of mid-IR frequency combs with GHz line spacing using iDFG.](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-09-23_at_12.41.27_PM.original.png)
![Generation of mid-IR frequency combs with GHz line spacing using iDFG.](https://caltechsites-prod.s3.amazonaws.com/resnick/images/Screen_Shot_2020-09-23_at_12.41.27_PM.max-1400x800.png)
Technical Details
- Near-IR soliton used for both lightwave and microwave oscillators
- Soliton and electro-optical combs together with PPLN can be integrated, enabling compact comb modules and mass production
- Agile control of the line spacing in mid-IR
Chengying Bao, Zhiquan Yuan, Heming Wang, Lue Wu, Boqiang Shen, Keeyoon Sung, Stephanie Leifer, Qiang Lin, and Kerry Vahala, "Interleaved difference-frequency generation for microcomb spectral densification in the mid-infrared," Optica 7, 309-315 (2020) https://doi.org/10.1364/OPTICA.382992
Contact: Kerry Vahala