PhD-student: Vibrating structures you can talk to: speech recognition with micro-mechanical neural networks

Date posted January 19, 2023
Type PhD positions

In the tale Ali Baba and the Forty thieves, saying ‘Open Sesame!’ opens the entrance to the thieves’ cave. Until now, the idea that an unpowered, inanimate object like a rock could respond to a spoken command has remained the stuff of folk tales. At the hypersmart matter group at AMOLF, we aim to turn this literary vision into a technological reality. Our objective, however, is not to protect a secret cave. We want to build smart devices (cell phones, smart speakers, IoT gadgets) that don’t consume power when they are not being used.

To be able to respond to events (like a person saying ‘Hey Alexa’), smart devices convert physical magnitudes (sound, acceleration, etc.) into electrical currents. These currents are then digitized and analyzed on a signal processor. Each of these processes constantly consumes energy, even when no word is being said. Consequently, batteries drain quickly even when we aren’t using the device. We aim to solve this problem using mechanical resonances: In the same way that a tuning fork vibrates when excited at its resonance frequency but not at other frequencies, we plan to build mechanical neural networks, brains of tuning forks, that respond when excited with a particular word but not others .

To accomplish this goal, we are looking for a motivated, ambitious student looking to join the vibrant team that will fabricate the first integrated circuit that processes information using mechanical waves instead of electrical signals – with nonlinear resonators taking the place of transistors. The Ph.D. student will lead the fabrication and characterization parts of the project, taking advantage of the state-of-the-art Amsterdam NanoLab. At the end of the Ph.D., we aim at having a completely passive chip (no batteries) that will activate a circuit in response to a spoken command.

Although the advertised Ph.D. position has an experimental focus, there will be opportunities for the student to get involved in the modelling and design efforts. Experience in cleanroom microfabrication and experimental nonlinear vibrations is appreciated but not mandatory. The student will develop scientific leadership skills through co-supervision of master students.

About the group

At the hypersmart matter group, we investigate the processing of information by structured elastic materials. We combine a fundamental interest to understand the limits and principles that govern information processing in physical systems with an applied drive to answer the low-energy and ubiquitous computing needs of the future. To achieve these goals, we combine advanced simulation and design methods with cleanroom fabrication techniques.


The applicant should have a bachelor’s and master’s degree in engineering (mechanics, electronics, computer science, chemical, telecom, nanotechnology, aerospace, etc.), physics, chemistry or a related discipline. The MSc-degree is a requirement to be eligible for a Dutch PhD examination. 

Terms of employment

The position is intended as full-time (40 hours / week, 12 months / year) appointment in the service of the Netherlands Foundation of Scientific Research Institutes (NWO-I) for the duration of four years, with a starting salary of gross € 2,539 per month and a range of employment benefits. After successful completion of the PhD research a PhD degree will be granted. Several courses are offered, specially developed for PhD-students. AMOLF assists any new foreign PhD-student with housing and visa applications and compensates their transport costs and furnishing expenses.

Contact info

Dr. Marc Serra Garcia
Group leader Hypersmart matter
Phone: +31 (0)20-754 7201

You can respond to this vacancy online via the button below.
Please annex your:
–  CV with 1-3 references
–  Academic transcript
–  Motivation letter explaining which of the two projects do you want to work on, why are you interested in this specific problem, how would you approach it and how it relates to your skills , interests and prior work.

Applications will be evaluated on a rolling basis and as soon as an excellent match is made, the position will be filled.

Online screening may be part of the selection.

AMOLF is highly committed to an inclusive and diverse work environment. Hence, we greatly encourage candidates from any personal background and perspective to apply.

Commercial activities in response to this ad are not appreciated.