Abstract
We study the optical reflectivity of three-dimensional (3D) photonic band gap
crystals with increasing thickness. The crystals consist of GaAs plates with
nanorod arrays that are assembled by an advanced stacking method into
high-quality 3D woodpile structures. We observe intense and broad reflectivity
peak with stop bands that correspond to a broad gap in the photonic band
structures. The maximum reflectivity quickly reaches high values even for a few
crystal layers. Remarkably, the bandwidth of the stop bands hardly decreases
with increasing crystal thickness, in good agreement with FDTD simulations.
This behavior differs remarkably from the large changes observed earlier in
weakly interacting 3D photonic crystals. The nearly constant bandwidth and high
reflectivity are rationalized by multiple Bragg interference that occurs in
strongly interacting photonic band gap crystals, whereby the incident light
scatters from multiple reciprocal lattice vectors simultaneously, in particular
from oblique ones that are parallel to a longer crystal dimension and thus
experience hardly any finite size effects. Our new insights have favorable
consequences for the application of 3D photonic band gap crystals, notably
since even thin structures reveal the full band gap functionality, including
devices that shield quantum bits from vacuum fluctuations.
crystals with increasing thickness. The crystals consist of GaAs plates with
nanorod arrays that are assembled by an advanced stacking method into
high-quality 3D woodpile structures. We observe intense and broad reflectivity
peak with stop bands that correspond to a broad gap in the photonic band
structures. The maximum reflectivity quickly reaches high values even for a few
crystal layers. Remarkably, the bandwidth of the stop bands hardly decreases
with increasing crystal thickness, in good agreement with FDTD simulations.
This behavior differs remarkably from the large changes observed earlier in
weakly interacting 3D photonic crystals. The nearly constant bandwidth and high
reflectivity are rationalized by multiple Bragg interference that occurs in
strongly interacting photonic band gap crystals, whereby the incident light
scatters from multiple reciprocal lattice vectors simultaneously, in particular
from oblique ones that are parallel to a longer crystal dimension and thus
experience hardly any finite size effects. Our new insights have favorable
consequences for the application of 3D photonic band gap crystals, notably
since even thin structures reveal the full band gap functionality, including
devices that shield quantum bits from vacuum fluctuations.
| Original language | English |
|---|---|
| Publisher | ArXiv.org |
| Number of pages | 10 |
| Publication status | Published - 17 Jan 2020 |