Sub-Nanometer Resolution Spectral Domain Computational Ghost Imaging Based on Dispersion Fourier Transformation

Computational spectral domain ghost imaging (CSGI), as an expansion of computational ghost imaging technique in the frequency domain, can achieve spectral detection through cross-correlation between the pre-designed optical spectral field and the corresponding detected intensity. Since the resolution of CSGI system depends directly on the granularity of the optical field, a high-resolution spectral modulator for the optical field manipulation is necessary. However, current spectral modulator is typically realized by the liquid-based programmable optical processor, whose highest spectral resolution is only 0.28 nm. To overcome the problem, a novel spectral modulation method based on dispersion Fourier transformation (DFT) is proposed. Through the DFT, the pressure of high-resolution spectral modulation can be transferred into the time-domain modulation, so the desired high-resolution spectral modulation can be achieved by the temporal modulation by a mature high-speed EO modulator. Based on this idea, a sub-nanometer resolution CSGI system is demonstrated with the maximum detection bandwidth of 0.66 THz and improves the spectral resolution up to 0.08 nm. The results show a significant potential for future spectroscopy, particularly in some spectral regions where high-resolution sensitive detectors are lacking.