READ ME File For 'Supporting Data for Doctoral Thesis 'Development of PPLN waveguides for IR upconversion detection and imaging''

Dataset DOI: 10.5258/SOTON/D3567

Date that the file was created: June, 2025

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GENERAL INFORMATION
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ReadMe Author: Noelia Palomar Davidson, University of Southampton [0000-0002-6413-5858]

Date of data collection: 2021-2024

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DATA & FILE OVERVIEW
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This dataset contains:

Figure7.2.xlsx
Countrate of 780nm photons generated in a Covesion Ltd. packaged PPLN waveguide for 1560nm SHG, pumped with 1590nm light

Figure7.4.xlsx
Signal from a lock-in amplifier, measuring backscattered 633nm photons at two different time constants of a raster scanned image of a hand-drawn cross pattern

Figure7.5.xlsx
Signal from a lock-in amplifier, measuring backscattered 1560nm photons at two different time constants of a raster scanned image of a checkerboard pattern

Figure7.7.xlsx and Figure7.7_SHG.png
Upconverted photon counts at approximately 780nm measured by SPAD detector, for an SFG process (.xlsx) and SHG process (.png), of a raster scanned image of the Quantic logo

Figure7.8.xlsx
Experimental phasematching spectra of 1950nm+1571nm SFG in a 16um wide waveguide ridge, with refractive index change 0.0049 and indiffusion depth 8.5um, and upconverted mode optical spectrum at the phasematching peak

Figure7.10.xlsx and Figure7.11.xlsx
Photon counts at 1571nm recorded by SNSPD detectors, for a raster scanned image of a checkerboard pattern

Figure7.13.xlsx
Photon counts at 870nm recorded by SNSPD detectors, from backscattered 1950nm light upconverted in a SFG PPLN waveguide pumped with 1571nm light, for a raster scanned image of a checkerboard pattern

Figure7.15.xlsx
Photon counts at 870nm recorded by SNSPD detectors, from backscattered 1950nm light upconverted in a SFG PPLN waveguide pumped with 1571nm light, for a raster scanned image of a checkerboard stencil

Figure7.17.xlsx
Photon counts at 870nm recorded by SNSPD detectors, from backscattered light with no active illumination of the target upconverted in a SFG PPLN waveguide pumped with 1571nm light, for a raster scanned image of a checkerboard pattern

Figure7.18.xlsx
Photon counts at 870nm recorded by SNSPD detectors, upconverted in a SFG PPLN waveguide as a function of pumped 1571nm power with blocked 1950nm collection  

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METHODOLOGICAL INFORMATION
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Description of methods used for collection/generation of data: 
Figure7.2.xlsx - Data was collected by Dr. Paolo Mennea. 1534nm and 1590nm light were combined using a WDM, plugged into the packaged waveguide module, and the output filtered. The output was connected to a channel of the Excelitas SPCM-AQ4C detectors, and the counts recorded.
Figure7.4.xlsx and Figure7.5.xlsx- Experiment was set up as in Figure 7.3 of the thesis, backscattered 633nm, or 1560nm, photons were measured using an amplified Si detector, or Ge detector) connected to a lock-in amplifier. The targets were a permanent marker hand-drawn cross on paper, and a printed checkerboard pattern. A LabVIEW project was developed in conjunction with Dr. Paolo Mennea to control the raster scanning of the Galvo mirrors and record and save the data from the lock-in amplifier. The speed of the scan was determined by the time constant of the lock-in amplifier.
Figure7.7.xlsx - Experiment was set up as in Figure 7.6 of the thesis, using a packaged PPLN waveguide for 1560nm SHG. The LabVIEW project was expanded to interface with the SPAD detectors and record photon counts, the scan rate was set to 1 pixel/s. The target was a Quantic logo color printed on paper.
Figure7.8.xlsx -  Experimental data was taken with a similar setup shown in Figure 3.12 of the thesis, a FBH870-10 filter was used to filter the SFG beam. Thorlabs BP209-VIS beam profiler was used to capture the mode profile images. The 870nm output light is coupled into an SM fibre and an OSA records the spectra of the upconverted mode at the phasematching peak.
Figure7.10.xlsx and Figure7.11.xlsx - Experiment was set up as in Figure 7.9 of the thesis, and data taken as described in Section 7.1.3.2. A target with high-reflectance PTFE sheet and black aluminium foil (BKF12) was made. The LabVIEW project was expanded to interface with the SNSPD detectors and record photon counts, and histograms of the photon counts. Imaging target was at approximately 90cm from the first collection lens, illumination and collection was done at 1571nm. A 30dB attenuator was added after the collection fibre. The pulse generator was used as a start point for the histogram data acquisition, where bin width was set to 40ps, total number of bins was 324 and the total capture duration of the histogram was 1s. The scan rate was determined by the total capture duration. 
Figure7.13.xlsx - Experiment was set up as in Figure 7.12 of the thesis, and data taken as described in Section 7.1.3.3. The same target with high-reflectance PTFE sheet and black aluminium foil (BKF12) was used as for Figure 7.10. Imaging target was at approximately 98cm from the first collection lens, illumination and collection was done at 1950nm, with a total capture duration of 1s.
Figure7.15.xlsx - Experiment was set up as in Figure 7.12 of the thesis, and data taken as described in Section 7.1.3.3. A target stencil was made by cutting out a checkerboard pattern from high-reflectance PTFE sheet. Imaging target was at approximately 98cm from the first collection lens, illumination and collection was done at 1950nm, with a total capture duration of 1s.
Figure7.17.xlsx - Experiment was set up as in Figure 7.12 of the thesis, and data taken as described in Section 7.1.3.3. The same target with high-reflectance PTFE sheet and black aluminium foil (BKF12) was used as for Figure 7.10. Imaging target was at approximately 98cm from the first collection lens, 1950nm illumination was blocked, the PPLN waveguide was pumped with 15mW of 1571nm light, the total capture duration for each pixel was 1s.
Figure7.18.xlsx - Experiment was set up as in Figure 7.12 of the thesis, and data taken as described in Section 7.1.3.3. Collection lens was blocked, only 1571nm light was pumped into the PPLN waveguide. A 16x16 pixel image was taken, and the photon counts are averaged over total number of pixels

Methods for processing the data: 
Figure7.2.xlsx - Data was plotted on a log log plot
Figure7.4.xlsx Figure7.5.xlsx - Data is saved as an image and as photon counts. The SHG data was only saved as an image.
Figure7.7.xlsx - Data is saved as an image and as photon counts
Figure7.8.xlsx - Signal power was divided by the transmission listed on the Thorlabs website for the components used (DMLP950,FBH870-10)
Figure7.10.xlsx and Figure7.11.xlsx - Resolution of the image is 16x16 pixels, covering a 6x6mm area, each row of the file corresponds to the histogram of a pixel, which can be plotted. All the columns are summed together to give a total counts per pixel image.
Figure7.13.xlsx - Total photon counts for a 16x16 resolution image, covering an 11x11mm area
Figure7.15.xlsx - Total photon counts for a 16x16 resolution image, covering an 11x11mm area
Figure7.17.xlsx - Total photon counts for a 16x16 resolution image, covering a 5x5mm area
Figure7.18.xlsx - Average photon counts for measured throughput 1571nm pump power, where the measured pump power is divided by the transmission of the optics

