Science 365, 1017–1020 (2019).

Spectrometers are integral instruments in numerous research applications, and miniaturized versions would have widespread applications. However, making micro-scale versions of standard instruments involves miniaturization of established components, which can be technically challenging or unfeasible. Yang et al. describe an alternative approach to miniaturization of standard spectrometers that uses a single compositionally engineered nanowire as the basis of the design. To keep things small, these nanowires combine elements that separate and detect light, and they are composed such that the spectral response varies along their length. Electronic probing of photocurrents and cross-referencing to a calibrated response function enables both monochromatic and broadband spectra to be reconstructed using this nanowire. The researchers incorporated the nanowire into a mapping system, and demonstrate spectral imaging on the centimeter scale as well as in situ absorption measurements of single cells.