Titania Woodpiles with Complete Three‐Dimensional Photonic Bandgaps in the Visible

Abstract

Titania woodpile photonic crystals are fabricated by a combination of stimulated-emission depletion direct laser writing and a novel titania double-inversion procedure. The procedure relies on atomic-layer deposition, which is also used to fine-tune the template geometry to maximize the gapsize. Angle- and polarization-resolved transmittance spectroscopy and a comparison with theory provide evidence for the first complete photonic bandgap in the visible.

Frequency‐Resolved Reciprocal‐Space Mapping of Visible Spontaneous Emission from 3D Photonic Crystals

“…[ 11 ] We go beyond previous experimental work [ 5,6,[12][13][14][15][16] in that we simultaneously measure the spontaneous emission emerging from a 3D photonic crystal versus frequency and versus wave vector in the 2D reciprocal space parallel to the photonic crystal surface. This means that we map, as much as fundamentally possible, the angular distribution of spontaneous emission inside a 3D photonic crystal versus frequency.…”

Photonic Structures in Biology: A Possible Blueprint for Nanotechnology

“…While diamond-based lattices -the champion structures 21 -have been achieved in photonic crystals operating at infrared wavelengths, [22][23][24][25][26][27] fabricating these lattices for use in the visible part of the electromagnetic spectrum has proven extremely difficult. 28,29 In contrast to our difficulties in fabricating diamond-based photonic lattices, beetles overcame this problem millions of years ago. Excellent examples are weevils, whose striking colouration is the result of light interacting with a diamond-based photonic crystal structure built into their exoskeleton scales made of cuticle.…”

“…Only very recently have engineering methods started to successfully extend into the visible range by fabricating diamondbased woodpile structures. 29,30 Self-assembly methods, on the other hand, have long been used to create photonic crystals with lattice constants spanning the infrared, visible and ultraviolet spectral ranges. 60,63 Nonetheless, except for some interesting examples in the ultraviolet, 60 self-assembly techniques have unfortunately been incapable of fabricating the most-desired diamond-based lattices.…”

“…8,9,[22][23][24][25][26][27][28][29][30] A basic design rule for a photonic crystal is that band gaps form at wavelength ranges of the electromagnetic spectrum that are of the same order of the periodic length (or lattice constant) of the photonic crystal. [13][14][15] For example, for a band gap within the microwave range, a periodic structure with millimetre lattice constants is needed, while band gaps in the infrared and visible portion of the spectrum form in periodic structures with lattice constants within the micrometre and nanometre ranges, respectively.…”

Additive nanomanufacturing – A review

“…99 The polymer structures written can also be used for casting of 3D structures from other materials like titania. 100 Maximising the resolution of MPP is of course an important goal, with Abbe's diffraction limit representing the typical limit. A recent review 101 summarised the advances in sub-diffraction limit DLW.…”