PMC

The H_Z field distribution at the resonance dip of (a) the complete ring structure at λ = 935 nm; (b) φ = 180° side-coupled structure at λ = 910 nm; (c) φ = 45° side-coupled structure at λ = 830 nm; (d) φ = 315° side-coupled structure at λ = 830 nm; (e) φ = 90° side-coupled structure at λ = 1385 nm; (f) φ = 270° side-coupled structure at λ = 1385 nm; (g) φ = 135° side-coupled structure at λ = 1185 nm; (h) φ = 225° side-coupled structure at λ = 1185 nm.

(a) Confinement loss curves of Λ = 1.8, Λ = 2 and Λ = 2.2 when N_a = 1.45 and N_a = 1.46. (b) Resonance wavelengths of Λ = 1.8, Λ = 2 and Λ = 2.2 when N_a changes from 1.43 to 1.49.

Spectral-angular correlations produce achromatic resonances in a micro-cavity. (a) When collimated broadband light is incident normally on a planar Fabry-Pérot cavity (top row), only a discrete set of wavelengths transmit (middle row) whose axial component of the wave vector inside the cavity is an integer multiple of k _o = π/d (identified by solid horizontal dashes in the bottom row); δλ is the resonance linewidth. (b) The cavity resonances are blue-shifted when light is incident at an angle θ. (c) By assigning each wavelength λ to an appropriate angle of incidence θ(λ), all the wavelengths can resonate and transmission becomes achromatic. One resonant order can extend here over a bandwidth exceeding the FSR. (d) Locus of resonant orders in spectral-angular space. Fixing the angle of one wavelength θ(λ _G), we can de-slant the resonance of a specific order (colored curve) by boosting and reducing a pre-compensation angle for each wavelength to produce an achromatic resonance (solid horizontal line). An angular spread Δθ at the input is required to de-slant the resonance between λ _B and λ _R. At the shorter wavelength λ _B, the incidence angle needs to be increased above θ(λ _G) by θ(λ _B) − θ(λ _G). The longer wavelength λ _R requires an incidence angle lower than θ(λ _G) by θ(λ _G) − θ(λ _R). Consequently, λ _R, λ _G, and λ _B all satisfy the resonance condition.

(Left) Dispersion relations of the core guided modes and the plasmon modes at temperature T = 22 C. (Insets) Electric field distributions of (a) core guided mode of x-pol at λ = 1.4 m; (b) core guided mode of y-pol at λ = 1.4 m; (c) core guided mode of x-pol at λ = 1.757 m (resonance wavelength); (d) core guided mode of y-pol at λ = 2.068 m (resonance wavelength); (e) plasmon mode of x-pol at λ = 1.75 m; (f) plasmon mode of y-pol at λ = 2.06 m.