Imaging turbulence with single-photon detector array technology
Lead Research Organisation:
Heriot-Watt University
Department Name: Sch of Engineering and Physical Science
Abstract
This is a PhD research project in Physics. The goal of this PhD is to develop technologies and methods for imaging turbulence in three dimensions at high speeds. The research will be based around single-photon detector array technologies that enable pulses of light to be tracked in 3D. The detector arrays have unprecedented single-photon sensitivity and enable precise timing of signals down to a few picoseconds. We will translate this technology from a lab based system to one suitable for real-time monitoring of atmospheric turbulence, ultimately leading to a technology suitable for single-photon sensitive astronomy.
People |
ORCID iD |
| Jonathan Leach (Primary Supervisor) | |
| Imogen Morland (Student) |
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| ST/S505407/1 | 30/09/2019 | 29/09/2023 | |||
| 2294127 | Studentship | ST/S505407/1 | 01/10/2019 | 31/03/2023 | Imogen Morland |
| Description | Light-in-flight (LIF) imaging is the measurement and reconstruction of light's path as it moves and interacts with objects. We are developing methods to track light as it propagates in the air in four dimensions - x, y, z, and time. In our recent work, we show how special cameras that can detect single photons can observe relativistic effects in light-in-flight measurements. The data is distorted by relativistic effects, resulting in light travelling towards/away from the camera appearing to travel faster/slower than the speed of light. Furthermore, focusing effects and Rayleigh scattering lead to light appearing to increase intensity as pulses travel away from the camera. By modelling these effects, light's true intensity-corrected path has been reconstructed in four dimensions (x,y,z,t). We are currently working on a method for measuring the depth of a target to nanometre precision using an autocorrelator and Fisher information. This high resolution system can be used in the future to measure the depth profile of an unknown sample such as cell membranes and DNA. |
| Exploitation Route | Understanding the intensity effects which occur in LIF imaging could have future applications in medical imaging, where the intensity of scattered photons gives information on the scattering source and its interaction with objects. |
| Sectors | Pharmaceuticals and Medical Biotechnology |
| URL | http://hwquantum.org/projects-1#/light-in-flight/ |
| Description | Difference Frequency Generation (DFG) of a 1550 nm LG mode using a 532 nm pump. |
| Organisation | University of the Witwatersrand |
| Country | South Africa |
| Sector | Academic/University |
| PI Contribution | I spent 5 weeks in South Africa working in the Structured Light Group on developing the experimental set-up. Since this was a new research field for me, I started by reading material provided by the group and learning how to simulate different LG orders in matlab. I then gained experience of using a DMD to produce LG modes whilst equipment for the main experiment was readied. My first experimental task was to couple 1550 nm light from a continuous wave (CW) laser diode into a single mode (SM) fibre so we could work with a Gaussian mode. I did this with the help of Andre, a visiting PhD student from Brazil. To do this, we used a series of aspherical and cylindrical lens' to correct for astigmatism and collimated the beam. The beam is then directed via 2 mirrors a short focal length Aspherical lens which focused light onto the fibre. By using a back alignment method, the laser was successfully coupled into the SM fibre. Then, I used a fibre amplifier to increase the output power from the SM fibre. As the 1550 nm laser diode was new to the lab, I then wrote a document explaing how to couple the fibre and opperate the laser and amplifier. I then directed this beam onto an SLM to check that we could modulate the beam and was able to produce a simple LG mode. Finally, I began directing the 1550 nm and 532 nm beams onto a BBO but didn't have sufficent time to finish the experiment. Once the experiment has been completed by Wagner (a postdoc in the group), I will create a figure for the experimental set-up in blender to put into the paper. |
| Collaborator Contribution | The Structured Light Group provided me with reading material to get up to speed on the reasearch and came up with the idea for the experiment. Wagner supported me throughout the project and helped me get started on the experiment whilst doing the theory for the experiment in the background. They also provided me with all of the equipment and space I needed within their research lab and paid for my accommodation while I stayed in Johannesburg and will finish the experiement. |
| Impact | None yet. |
| Start Year | 2022 |