μm⁻¹
per micrometer
Wavenumberexact by definition
The reciprocal micrometre is 10⁶ m⁻¹. It is used in near-field optics, plasmonics and photonic crystal work, where feature spacings are sub-micrometre and reciprocal-space plots run over a few inverse micrometres.
| 1 μm⁻¹ | 1,000,000 m⁻¹ |