In one implementation, a spectral microscope may comprise a substrate with a planar lens, the planar lens including a phase profile including an axial focus and an oblique focus, a light source to excite a signal of a particle among a plurality of particles, and a detector to receive light generated from the light source from the axial focus of the planar lens and a spectral color component of the excited signal of the particle from the oblique focus of the planar lens.