  Hyperspectral imaging is a technique that allows for the creation of
multi-color images. At terahertz wavelengths, it has emerged as a prominent
tool for a number of applications, ranging from non-ionizing cancer diagnosis
and pharmaceutical characterization to non-destructive artifact testing.
Contemporary terahertz imaging systems typically rely on non-linear optical
down-conversion of a fiber-based near-infrared femtosecond laser, requiring
complex optical systems. Here, we demonstrate hyperspectral imaging with
chip-scale frequency combs based on terahertz quantum cascade lasers. The dual
combs are free-running and emit coherent terahertz radiation that covers a
bandwidth of 220 GHz at 3.4 THz with ~10 {\mu}W per line. The combination of
the fast acquisition rate of dual-comb spectroscopy with the monolithic design,
scalability, and chip-scale size of the combs is highly appealing for future
imaging applications in biomedicine and in the pharmaceutical industry.
