Quantum Optoelectronics

Abstract:

These data all relate to GaAs photonic crystal waveguides with SU-8 photoresist disks patterened on top them to create cavities. The waveguides contain high-density embedded InGaAs quantum dots which couple to the cavity modes.

The folder fig2 contains data from an FDTD simulation measuring cavity Q factor and mode volume against disk diameter.

The folder fig3 contains micro-photoluminescence (uPL) spectra of the waveguides taken before and after cavity fabrication. See fig3/readme.txt for more information.

The folder fig4 contains the Q factor, disk thickness, and disk diameter data for all the devices studied.

The folder fig5 contains a scanning electron microscope image and associated 2D uPL map of one of the cavities.

More information and details of file formats is contained in the following files:
readme.txt
asc_file_format.txt
fig2/readme.txt
fig3/readme.txt

Note that those .txt files use unix-style line endings (LF), not Windows-style ones (CRLF). They may not display correctly in Notepad. The difficulty of achieving reliable spectral and spatial overlap is a serious problem when fabricating photonic crystal (PhC) cavities around self-assembled quantum dots. We present a method for using photoresist to optically fabricate heterostructure cavities in a PhC waveguide with a combined photolithography and micro-photoluminescence spectroscopy system. We confirm the creation of cavity modes with high quality factors (mean = 3.8*10^3, maximum = 7.4(2)*10^3). This method offers a promising route towards bright, on-chip single photon sources for quantum information applications.

Abstract:

The data was taken with temperature-dependent time-integrated, time-resolved, and polarisation-resolved microphotoluminescence, and Hanbury Brown and Twiss experiments from 5 to 250 K. The purpose is to investigate whether non-polar a-plane quantum dots can act as high temperature single photon sources with optical polarisation control beyond the 200 K Peltier cooling threshold. All data were taken during April-May 2016.

Abstract:

The data were created from k.p simulation, polarization-resolved microphotoluminescence, and Hanbury Brown and Twiss experiments, from 2015 to 2016. The data were created to demonstrate the rigorous generation of polarised single photons with a deterministic axis, and to explain the origin of high polarisation degree and fixed axis, in a-plane InGaN quantum dots. All data were hence used in Figures 2-5 in the publication “Direct generation of linearly polarized single photons with a deterministic axis in quantum dots”

Abstract:

Creation: 11.2016-1.2017 Raw data + analysed data by Matlab and Origin For each figure the rawdata underlying it was added as well.

Abstract:

Exfoliated crystalline niobium oxides that contain exposed but interconnected NbO 6 octahedra with different degrees of structural distortion and defects are known to catalyze Brønsted acid (BA), Lewis acid (LA), and photocatalytic (PC) reactions efficiently but their structure–activity relationships are far from clear. Here, three exfoliated niobium oxides, namely, HSr 2 Nb 3 O 10 , HCa 2 Nb 3 O 10 , and HNb 3 O 8 , are synthesized, characterized extensively, and tested for selected BA, LA, and PC reactions. The structural origin for BA is associated mainly with acidic hydroxyl groups of edge-shared NbO 6 octahedra as proton donors; that of LA is associated with the vacant band position of Nb 5+ to receive electron pairs from substrate; and that of PC is associated with the terminal Nb=O of NbO 6 octahedra for photon capture and charge transfer to long-lived surface adsorbed substrate complex through associated oxygen vacancies in close proximity. It is believed that an understanding of the structure–activity relationships could lead to the tailored design of NbO x catalysts for industrially important reactions.