Dual-comb single-pixel imaging in both amplitude and phase

Dual comb spectroscopy (DCS) is based on the combination of Fourier transform spectroscopy with an optical frequency comb (OFC), and has a spectral resolution of MHz order over a spectral range of several tens THz. Furthermore, nonmechanical time-delay scanning enables the rapid data acquisition. While DCS imaging is required for hyperspectral imaging, an imaging sensor cannot be used for DCS imaging because of a slow response time compared to the temporal evolution of interferogram signal. Therefore, it is essential to acquire the interferogram signal by use of a single-channel detector while scanning the sample position or the focal point. If DCS imaging can be achieved without the need for such scanning, the application field of the DCS imaging will be largely expanded. One promising method to achieve the scanless imaging is a single-pixel imaging (SPI). SPI enables scan-less imaging by use of optical spatial coding on the sample with a single-channel detector. Also, the spatial averaging effect improves an image quality. In this paper, we present combination of DCS with SPI, namely a DCS-SPI. DCS-SPI provides 12,000 mode-resolved hyperspectral images in both amplitude and phase at a spatial resolution of 46 μm without the need for mechanical scanning. Furthermore, we determined thickness of a chromium layer from a phase image in the near-infrared wavelength region.