JOURNAL ARTICLE

Long-wavelength infrared upconversion time-stretch spectroscopy.

  • Published In: Applied Physics Letters, 2024, v. 125, n. 7. P. 1 1 of 3

  • Database: Academic Search Ultimate 2 of 3

  • Authored By: He, Linzhen; Wu, Han; Wang, Weizhe; Hu, Bo; Yang, Xuemei; Liang, Houkun 3 of 3

Abstract

This article focuses on the development and experimental demonstration of broadband long-wavelength infrared (LWIR, 8–10 μm) time-stretch spectroscopy, a technique essential for high-speed molecular fingerprint region analysis. The method combines femtosecond LWIR light generation using a LiGaS₂ (LGS) crystal-based optical parametric amplifier, chirped pulse upconversion via difference-frequency generation (DFG) with a 1 μm pump pulse, and time-stretch detection employing a 25-km dispersion shift fiber (DSF) optimized for near-infrared (NIR) wavelengths around 1.14–1.19 μm. The system achieves a spectral resolution of 1.07 cm⁻¹ at an acquisition rate of 200,000 spectra per second, demonstrated by measuring the absorption spectrum of a polystyrene film with results consistent with commercial Fourier-transform infrared (FTIR) spectroscopy. This approach addresses previous limitations in LWIR spectroscopy by enabling high-speed, high-resolution measurements in the molecular fingerprint region and suggests potential for further improvements using higher repetition rate pump sources and extended spectral coverage.

Additional Information

  • Source:Applied Physics Letters. 2024/08, Vol. 125, Issue 7, p1
  • Document Type:Article
  • Subject Area:Chemistry
  • Publication Date:2024
  • ISSN:0003-6951
  • DOI:10.1063/5.0218110
  • Accession Number:179085513
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