OPEN POSITIONS

We always have interesting topics for Bachelor, Master and PhD Projects. Some examples are listed below.

If you are interested in our group's work please contact Prof. Pernice for further information.

Superconducting nanowire single-photon detectors (SNSPDs) have become fundamental components in quantum communication, computing, and photonic circuits due to their high efficiency, low dark counts, ultra-fast response times, and low timing jitter. Their performance is partially limited by the read-out and biasing electronics that feed a constant current through the nanowire and amplify the voltage spike induced by a photon detection.

Research Objectives & Questions

Primary Objective: Designing and characterizing a biasing and readout printed circuit board (PCB) at cryogenic temperatures for single photon detection.

Research Questions: Which electrical components work best at cryogenic temperatures and high bandwidths? How can the amplification of the detection signal be maximized while keeping the timing jitter low and count rate sufficient? Which design allows for maximum number of readouts simultaneously while keeping the heat production sufficiently low?

For further information, please see the full proposal and contact Kilian Welz or Prof. Pernice.

The Silicon-on-insulator (SOI) platform offers several advantages of high refractive index contrast and CMOS compatability which make it ideal for integrated photonic devices. Several devices have been conceived such as wave-guides, which guide the light on-chip, similarly to a fiber-optics cable, and grating couplers, which couple the light from an out of plane light source into the waveguide. The geometric dimensions of the photonic devices, for example the wave-guide width, influence their ability to manipulate light.

Research Objectives & Questions

Primary Objective: Optimize the performance by computational simulation of SOI devices and varying geometric parameters.

Secondary Objectives: Understanding nanofabrication limitations on device properties like the sidewall roughness and optimizing the fabrication recipe accordingly. For this, the devices’ optical properties as well as their microscopic properties need to be measured.

Research Questions: Which design parameters yield the optimal optical properties for which fabrication recipe? How do the parameters of the fabrication recipe change the result and can this be compensated with a different design?

For further information, please see the full proposal and contact Kilian Welz or Prof. Pernice.

Superconducting nanowire single-photon detectors (SNSPDs) have become fundamental components in quantum communication, computing, and photonic circuits due to their high efficiency, low dark counts, ultra-fast response times, and low timing jitter. This performance is closely tied to the quality of the superconducting thin films, which significantly influences efficiency, timing jitter, and maximum count rate. SNSPDs work by photon absorption disrupting the superconducting state, generating measurable voltage pulses. The film's properties, such as thickness, crystallinity, and uniformity, are crucial for efficient detection and fast response. NbN is favored for its high superconducting transition temperature (Tc), critical current, and optical absorption. This thesis focuses on optimizing NbN thin film deposition via high-temperature magnetron sputtering, aiming to enhance film quality and improve the performance of photonic-integrated SNSPDs. Sputtering allows fine control over film characteristics, including thickness, composition, and grain structure, but parameters like power, pressure, and substrate temperature must be optimized for ideal superconducting and optical properties. Previous studies highlight the importance of film quality in SNSPD performance, providing a basis for optimizing thin film deposition in this work.

Research Objectives & Questions

Primary Objective: Optimize sputtering deposition parameters of NbN thin films to enhance the performance of photonic-integrated SNSPDs.

Secondary Objectives: Characterize structural, compositional, and superconducting properties of the films and correlate deposition parameters with electrical and optical performance at both room and cryogenic temperatures.

Research Questions: Which sputtering parameters (e.g., power, substrate temperature, gas pressure and concentration) most impact the superconducting and optical properties of NbN films?  How do these parameters influence detector efficiency, timing jitter, and count rates?

Methodology

Thin Film Deposition & Optimization:

The student will learn to operate a high-temperature magnetron sputtering tool to deposit NbN thin films onto substrates

Characterization Techniques:

·       Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDS)

·       Profilometry

·       Transmission Electron Microscopy (TEM)

·       Cryogenic Measurements

·       Electrical Characterization

Expected Outcomes & Impact

The optimization of NbN thin film deposition is expected to improve the performance characteristics of SNSPDs, making them faster and more efficient. The ability to produce thin films with controlled properties will directly contribute to the development of ultra-fast detectors with high efficiency and low timing jitter. This work could serve as a basis for future advancements in the field of superconducting photon detectors, particularly for applications in quantum technologies and integrated photonics.

For further information, please see the full proposal and contact Dr. Simone Ferrari or Prof. Pernice.

This project is to develop an on-chip photonic switch for quantum computers, leveraging light to manipulate atoms and unlock unprecedented computational speed, efficiency, and security.

By joining this interdisciplinary project, you will work closely with a team of experienced experts in photonics, electronics and material science, and gain hands-on experience on realizing an electro-optic chip - from design and simulation to characterization and measurement.

We are looking for highly self-motivated students with curiosity and a passion for technology. Apply and be part of a team that's lighting the way to a quantum future.

For further information, please contact Xinyu Ma or Prof. Pernice.

The testing and development of photonic devices, such as modulators, waveguides, and resonators, often face challenges due to the high cost and limited availability of specialized equipment. One fundamental tool is a tunable wavelength source, which allows researchers to change the wavelength (or color) of light over a range to study how these devices respond to different wavelengths. This process, known as wavelength sweeping, is essential for characterizing the behavior and performance of photonic devices. To make this technology more affordable and scalable, the project aims to develop a new kind of tunable light source using a MEMS-based VCSEL (Vertical-Cavity Surface-Emitting Laser).

Research Questions
1. Can a modified off-the-shelf MEMS VCSEL tunable wavelength source achieve the necessary spectral resolution for photonic component characterization?
2. How does this engineered solution compare to existing commercial tunable sources in terms of cost, performance, and scalability?

For further information, please see the full proposal and contact Ravi Pradip, Dr. Simone Ferrari or Prof. Pernice.

Integrated photonics is a rapidly advancing field with applications in telecommunications, sensing, and quantum technologies. Introducing its fundamental concepts to undergraduates and high school students provides a unique opportunity to engage them with hands-on experience in optics and photonics, potentially inspiring future study and research in this area. This project aims to design and develop an educational kit to guide students through key principles of integrated photonics, offering practical experience to support theoretical learning.

For further information, please see the full proposal and contact Dr. Simone Ferrari or Prof. Pernice.

Photonic Integrated Circuits (PICs) are met in a variety of applications from sensing and parallel photonic computing to quantum computing on different platforms. This thesis is located in a project environment aiming for quantum computing in neutral atoms. Fabricated with precision of few nanometers, waveguides are the most basic building blocks of PICs. Their quality and specifications are key to any passive or active photonic element. Surface quality and etch profile directly influence propagation losses, and therefore transmission all over a PIC.

In this thesis the candidate will measure waveguide profiles of fabrication tests with nanometer resolution technology like scanning electron microscopy (SEM) and develop parameter sets for ongoing fabrication tests. The candidate will provide an analysis of the relationship between the process parameters and the resulting profile, etch rate and surface qualities. In addition, an analysis of the transmission of UV light depending on the waveguide profile should be developed.

For further information please contact Klara Meyer-Hermann or Prof. Pernice.

Are you passionate about cutting-edge research and eager to dive into the fascinating world of artificial intelligence and neural networks? If so, we have an exciting opportunity waiting for you! We are currently seeking dedicated and motivated students to join our team for a project focused on the implementation of phase change materials in neural networks and the design of laser setups in our advanced laboratory. As a part of this project, you will actively contribute to the design and implementation of novel laser setups, allowing an in-depth analysis of these materials in terms of behavior and characteristics. By joining our team, you will have the opportunity to:

1. Develop your scientific skills and expand your knowledge in an area of research that has far-reaching implications.
2. Learn and contribute to the fabrication of photonic chips, pushing the boundaries of what is currently possible in the field.
3. Gain hands-on experience in material characterization methods, such as scanning electron microscopy, energy dispersive X-ray spectroscopy.

Our experienced team members and specialists will guide you throughout the project, providing valuable mentorship and support. This experience will not only enhance your academic profile but also provide you with a competitive edge in your future career endeavors.

If you are a driven and enthusiastic student with a background in physics, photonics, or a related field, we encourage you to seize this incredible opportunity. Contact us and join us in the development of next-generation artificial intelligence and edge computing technologies.

For further information please contact Shabnam Taheriniya or Prof. Pernice.

For more open PhD projects, please contact Prof. Pernice.