Spectrally-encoded labeling and reading

A spectrally-encoded label, comprising a spectrally-selective optical element having a label spectral signature, wherein:

• the label spectral signature is determined according to a spectral-encoding scheme so as to represent predetermined label information within the spectral encoding scheme;
• the label emits output light in response to input light selected by the label spectral signature of the optical element;
• the spectrally-selective optical element has at least one spatially-varying optical property;
• the spatially-varying optical property of the spectrally-selective optical element varies substantially continuously over an area of the optical element;
• the continuously-varying area of the optical element comprises at least two distinct areal segments each having a corresponding areal spectral signature;
• the areal spectral signatures of an active fraction of the areal segments contribute to the label spectral signature;
• and
• the areal spectral signatures of a remaining deactivated fraction of the areal segments do not contribute to the label spectral signature.

A spectrally-encoded label, comprising a spectrally-selective optical element having a label spectral signature, wherein:

• the label spectral signature is determined according to a spectral-encoding scheme so as to represent predetermined label information within the spectral encoding scheme;
• the label emits output light in response to input light selected by the label spectral signature of the optical element;
• the spectrally-selective optical element comprises a diffraction grating;
• and
• diffractive elements of the grating are circular.

A spectrally-encoded label, comprising a spectrally-selective optical element having a label spectral signature, wherein:

• the label spectral signature is determined according to a spectral-encoding scheme so as to represent predetermined label information within the spectral encoding scheme;
• the label emits output light in response to input light selected by the label spectral signature of the optical element;
• the spectrally-selective optical element comprises a diffraction grating;
• and
• the grating surface is curved.

A spectrally-encoded label, comprising a spectrally-selective optical element having a label spectral signature, wherein:

• the label spectral signature is determined according to a spectral-encoding scheme so as to represent predetermined label information within the spectral encoding scheme;
• the label emits output light in response to input light selected by the label spectral signature of the optical element;
• the spectrally-selective optical element comprises a diffraction grating;
• and
• the grating is a chirped grating.