Nature Communications (Jan 2024)

Scalable integrated two-dimensional Fourier-transform spectrometry

  • Hongnan Xu,
  • Yue Qin,
  • Gaolei Hu,
  • Hon Ki Tsang

DOI
https://doi.org/10.1038/s41467-023-44518-y
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 10

Abstract

Read online

Abstract Integrated spectrometers offer the advantages of small sizes and high portability, enabling new applications in industrial development and scientific research. Integrated Fourier-transform spectrometers (FTS) have the potential to realize a high signal-to-noise ratio but typically have a trade-off between the resolution and bandwidth. Here, we propose and demonstrate the concept of the two-dimensional FTS (2D-FTS) to circumvent the trade-off and improve scalability. The core idea is to utilize 2D Fourier transform instead of 1D Fourier transform to rebuild spectra. By combining a tunable FTS and a spatial heterodyne spectrometer, the interferogram becomes a 2D pattern with variations of heating power and arm lengths. All wavelengths are mapped to a cluster of spots in the 2D Fourier map beyond the free-spectral-range limit. At the Rayleigh criterion, the demonstrated resolution is 250 pm over a 200-nm bandwidth. The resolution can be enhanced to 125 pm using the computational method.