Photon Counting Detectors: from quantum cryptography to space communication.

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  Areas: Nanotechnology, Information and Communication Technology, Applied Physics, Photonics.

 
The goal of this experimental project is to design, construct and test nanowire based photonic detectors with a single photon sensitivity.
Background:
Generation, detection, and quantum manipulation of single photons is one of the highest interest in many research fields: secure communication (quantum key distribution or quantum cryptography), quantum computing, deep space communication, etc. The fastest and most sensitive single photon detectors are superconducting nanowire detectors, which utilize photon assistance brakeage of the super-current in very narrow thin film bridges (about 100nm wide). This leads to a large voltage pulse, which is registered with pulse counters. The reset time (superconductivity recovery time) has to be as short as possible in order to enable high speed data communication. The presently utilized superconductors are: NbN, NbTiN, WSi. Although providing a state-of-the-art performance, they hit a fundamental limit of their reset time of about 1ns (1Gbs). With this project you will be given a chance to participate in development of novel materials, detectors, techniques aiming for very data rate photon counting.
Project description:
This project will explore fundamentals of single photon detection in thin films nanowires made of magnesium deboride (MgB2). High quality film deposition has recently been established in our group, providing high crystal quality, high superconducting transition temperature (35-40K), and low normal state resistivity. We expect this material to show a factor of 5-7 lower magnetic field penetration depth with a 25-50 reduction of the reset time.
Methods:
In this experimental project, depending whether you choose a 30 or a 60 credit option, you will be doing:
• thin film deposition in our HPCVD system,
• learning e-beam lithography techniques,
• thin film processing,
• dc and optical characterization of the obtained detectors.
You will acquire experience with state of the art equipment, and learn about exotic phonic applications. The project presumes extensive literature studies, Clean Room work, laboratory work with IR lasers and broadband microwave readout schemes, and result analysis.
 
This project is suitable for MSc student from Nanotechnology, Applied Physics (Teknisk Fysik), Wireless, Photonics and Space Engineering Master Programs. The project can be tailored either for 30 or 60 credits.
 
Contact: Dr. Sergey Cherednichenko, serguei@chalmers.se, 031-7728499., MC2 / room C623

Published: Fri 20 May 2016.