Abstract: A tunable photonic crystal device comprising: alternating layers of a first material and a second material, the alternating layers comprising a responsive material, the responsive material being responsive to an external stimulus, the alternating layers having a periodic difference in refractive indices giving rise to a first reflected wavelength; wherein, in response to the external stimulus, a change in the responsive material results in a reflected wavelength of the device shifting from the first reflected wavelength to a second reflected wavelength.

Abstract: A tunable photonic crystal device comprising: alternating layers of a first material and a second material, the alternating layers comprising a responsive material, the responsive material being responsive to an external stimulus, the alternating layers having a periodic difference in refractive indices giving rise to a first reflected wavelength; wherein, in response to the external stimulus, a change in the responsive material results in a reflected wavelength of the device shifting from the first reflected wavelength to a second reflected wavelength.

Abstract: A photonic crystal device including a photonic crystal material and an activation surface. The photonic crystal material exhibits a first reflectance spectrum in an unactivated state, and, in response to mechanical stimulation, exhibits a second reflectance spectrum in an activated state. Application of a force at an activation portion of the activation surface offset from a material-supporting portion of the activation surface causes a deformation of the photonic crystal material sufficient to bring the photonic crystal material to the activated state.

Abstract: A photonic crystal device comprising: a photonic crystal material having an initial ordered structure and a viewing surface, the initial ordered structure giving rise to a first optical effect detectable from the viewing surface; and a removal layer removably attached with the viewing surface or an opposing surface of the photonic crystal material opposite to the viewing surface; wherein mechanical removal of at least a portion of the removal layer results in a structural change in at least a portion of the initial ordered structure of at least a portion of the photonic crystal material respective to the portion of the removed removal layer, thereby resulting in a changed portion different from the initial ordered structure, the changed portion giving rise to a second optical effect detectable from the viewing surface and detectably different from the first optical effect.

Abstract: A compressible photonic crystal comprising a polymer with an ordered array of voids, the photonic crystal having a reflectance in a first wavelength range for light incident to its incident surface and its opposing incident surface; wherein compression against at least a portion of at least one of the surfaces shifts the reflectance to a second wavelength range in at least that portion of that surface. The crystal may be used in authentication devices of various types.

Abstract: A security and/or authentication device comprising: a compressible photonic crystal having an ordered array of voids, the photonic crystal having a reflection peak, wherein compression against at least a portion photonic crystal results in a decrease of intensity of the reflection peak in at least that portion.

Abstract: The present disclosure provides methods, systems and devices for a photonic crystal combinatorial sensor. The photonic crystal sensor may include an array of photonic crystal materials, wherein each photonic crystal material has a reflected wavelength in a respective initial wavelength range. At least one a first one of the photonic crystal materials may be configured to have a response to an external stimulus different from at least a second one of the photonic crystal materials, the different response resulting in a change in the reflected wavelength of the first photonic crystal material that is an optically detectable difference from the second photonic crystal material. The optically detectable difference may provide an optically detectable response pattern of reflected wavelengths in the array. The sensor may be reversible and reusable.

Abstract: A tunable photonic crystal device comprising: alternating layers of a first material and a second material, the alternating layers comprising a responsive material, the responsive material being responsive to an external stimulus, the alternating layers having a periodic difference in refractive indices giving rise to a first reflected wavelength; wherein, in response to the external stimulus, a change in the responsive material results in a reflected wavelength of the device shifting from the first reflected wavelength to a second reflected wavelength.