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Project wiki for the Module QT5201U - AY20/21S2
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Project proposals
Here, links/short descriptions to projects should be listed.
This is just a dummy project.
Basically we are now trying to build a wavemeter which can measure wavelength from 1200nm to 1800nm because the measurement tool for these lasers is not available now in our lab. It is based on Michelson interferometer.
Proof-of-concept experiment to show how one may use commonly-available materials to measure difference in laser path lengths to sub-millimeter precision with a copper target (TBC). This experiment is done using a 355nm, 120 MHz, 10ps pulsed laser. Upon showing that such a measurement is possible, we shall go on to explore some for-fun applications of this "technology" and see how far and precise we can get.
With a combination of the Saturation Spectroscopy and Frequency Modulation techniques, we aim at stabilizing the wavelength of a Diode Laser at approximately 780.241 nm which corresponds to the transition (also known as D2 line) of Rubidium 87. Additionally we will implement in the experiment a Red Pitaya, which is a minicomputer capable of replacing things like an Oscilloscope, Function Generator and PID controller. Therefore reducing the space needed for the experiment.
NMR has been the workhorse for the experimental implementation of quantum protocols, allowing exquisite control of systems up to seven qubits in size. However, there exists some experimental limitations in terms of the cross-talk, coupled evolution, instrumental errors and so on. Thanks to the current advanced pulse techniques, we can reduce these influences and extend this technique to a new stage that the experimental limits can be neglected. In this experiment, we try to use composite pulses to compensate RF field strength variations and frequency offsets.
This project aims to build a Fabry-perot interferometer (also called Etalon) that works at the optical telecommunication wavelengths (1260nm-1625nm). This depicted etalon is made out of a single piece of polished silicon wafer with a thickness of about 100μm. The free spectral range (FSR) of the etalon can be adjusted by changing its thickness through temperature tuning. We will also explore the possibility of applying highly reflective (HR) coatings to the silicon wafer to achieve a high cavity finesse and a narrow transmission line-width.
This project aims to perform a trial pre-experiment based on the cQED architecture including simulation, calibration, microwave control pulse programming, and so on. The 3D superconducting cavity sample is anchored to the MXC flange inside the Bluefors dilution refrigerator to reach a temperature of around 10mK. On the other hand, the generation of microwave control pulses and the acquisition of output signals are handled by a QM quantum control device, connecting the sample via the control lines and the output lines accordingly. Hence, we can realize several bosonic states via cavity driving and qubit control.
Not an active project! Just a random idea, might be fun to try. As discussed during the AOM lecture, a media with a slow speed of sound is preferred for construction of AOMs. The most common material through which the speed of sound is very very slow would be air. Unfortunately, atmospheric air by itself is very chaotic and is not optimal for use in the context of an AOM. Given these considerations, is it possible for a small chamber of a laminar flow of air, modulated by some acoustic frequency, act as an effective AOM?
Material requests
Please add stuff we should organize one way or the other here:
- more space
- cookies...
Stuff to be covered in the lecture slots on Mondays (sometimes Tuesdays as well)
Feel free to add topics or aspects to this list. At the moment, this is just a copy of the tentative syllabus:
| Date | Topic | Description |
|---|---|---|
| 18.1.2021 | Paraxial optics, part 1 | Optical systems often work with Gaussian beams. We cover practical design techniques like the ABCD matrix formalism for simple optical systems. |
| 19.1.2021 | Paraxial optics, part 2 (only first part of lecture) | |
| 25.1.2021 | Optical cavities, part 1 | Many optical techniques require to work with optical cavities. We cover how to design them, and how to couple light into very basic devices. This lecture covered some theory basics. |
| 26.1.2021 | Optical cavities, part 2 | Some more aspects of optical cavities, and dielectric coatings for mirrors and such |
| 1.2.2021 | Optical fiber technology | Some properties of optical fibers as the most common optical waveguide are covered, including optical mode spectrum, dispersion and transmission properties. |
| 8.2.2021 | Optical modulators, part 1 | Many optical modulation techniques require rely on devices or materials where optical properties can be changed electrically; we cover accousto-optical and electro-optical devices, as well as liquid crystal systems. |
| 9.2.2021 | Optical modulators, part 2 | |
| 15.2.2021 | Homodyne detection techniques | Measurement of optical fields in many continuous variable scenarios require knowledge of optical homodyning and heterodyning techniques. These techniques, similar to their radiofrequency counterparts, rely on multiplying field amplitudes. |
| 1.3.2021 | Frequency control of laser systems, part 1 | Many laser systems in quantum technologies require to have a well-defined frequency relationship with atomic transitions or solid state qubits. We cover typical techniques how laser systems can be controlled to a high enough accuracy, utilizing spectroscopy techniques and control systems. |
| 2.3.2021 | Frequency control of laser systems, part 2 | |
| Practical aspects of superconducting systems | We cover different materials, transition temperatures, temperature measurement techniques and thermal insulation / conduction techniques. | |
| Generating pulse sequences | Many quantum systems require short control pulses, either in form of optical pulses or radiofrequency pulses. We present a few techniques to generate such control pulses | |
| Interface to computers | High level interfacing between computers and electronic hardware: Simple python scripting, standard device languages | |
| High voltage techniques | Working with high voltages requires a spectrum of techniques that is differing from more conventional electronics. A few aspects (field emission, dielectric strength, specific components) are covered. |
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