X-ray imaging non-destructively identifies functional 3D photonic nanostructures

Abstract

To investigate the performance of three-dimensional (3D) nanostructures, it is vital to study in situ their internal structure non-destructively. Hence, we perform synchrotron X-ray holographic tomography on exemplary 3D silicon photonic band gap crystals without irreversible preparation steps. Here, we obtain real space 3D density distributions of whole crystals buried on 2 mm^2 beams with 20 nanometer resolution. Our X-ray results identify why structures that look similar in scanning electron microscopy have vastly different nanophotonic functionality: One crystal with a broad photonic gap reveals 3D periodicity as designed ("Good"), a second structure without gap reveals a buried void ("Bad"), a third one without gap is shallow due to fabrication errors ("Ugly"). We conclude that X-ray tomography is a crucial tool to critically assess 3D functional nanostructures.

arXiv comment8 pages, 5 figures, includes supplementary material

References in corpus (10)

• Past Achievements and Future Challenges in 3D Photonic Metamaterials
• PyHST2: an hybrid distributed code for high speed tomographic reconstruction with iterative reconstruction and a priori knowledge capabilities
• Lasing oscillation in a three-dimensional photonic crystal nanocavity with a complete bandgap
• Optical extinction due to intrinsic structural variations of photonic crystals
• Inhibited spontaneous emission of quantum dots observed in a 3D photonic band gap
• Signature of a three-dimensional photonic band gap observed on silicon inverse woodpile photonic crystals
• The role of fabrication deviations on the photonic band gap of 3D inverse woodpile nanostructures
• Revealing three-dimensional structure of individual colloidal crystal grain by coherent x-ray diffractive imaging
• Reflectivity calculated for a 3D silicon photonic band gap crystal with finite support
• Method to make a single-step etch mask for 3D monolithic nanostructures

Cited by in corpus (7)

• Light in correlated disordered media
• Spatially shaping waves to penetrate deep inside a forbidden gap
• Experimental probe of a complete 3D photonic band gap
• Enhanced Absorption in thin and ultrathin silicon films by 3D photonic band gap back reflectors
• Observation of mutual extinction and transparency in light scattering
• Non-utopian optical properties computed of a tomographically reconstructed real photonic nanostructure
• Symmetries and Wavefunctions of Photons Confined in 3D Photonic Band Gap Superlattices