During her PhD studies, Trishala Mitra worked on cavity optomechanics using suspended ultrathin membranes. Such membranes are particularly well suited for interacting with light in optical resonators, as they combine low mass with excellent vibrational properties and can be nanostructured to act as lightweight resonant mirrors.

Trishala worked on the fabrication and the optical and mechanical characterisation of silicon nitride membranes patterned with subwavelength grating structures. She investigated how these nanostructures support optical resonances that strongly enhance the reflectivity of the membranes at specific wavelengths and how such resonant mirrors can be integrated into ultracompact optical cavities. The work further explored how the radiation pressure of the light inside these cavities can be used to affect their vibrations.

These findings contribute to the understanding of light–matter interaction in optomechanical systems and provide new tools for precision measurements and sensing.

The PhD degree was completed at the Department of Physics and Astronomy, Faculty of Natural Sciences, Aarhus University.

This summary was prepared by the PhD student.

Time: Monday, 9^th March 2026,  at 13:00.
Place: Building 1525, room: 626, Lecture Theatre: Det Skæve Rum, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000 Århus C
Title of PhD thesis: Cavity optomechanics with suspended resonant mirrors.
Contact information: Trishala Mitra, e-mail: trish@ece.au.dk, tel.: +45 24220104
Members of the assessment committee:
Associate Professor Richard Norte, Delft University of Technology, Netherlands
Professor Jesper Mørk, Danish Technical University, Denmark
Associate Professor Jill Miwa, Department of Physics and Astronomy, Aarhus University (chair), Denmark
Main supervisor: Associate Professor Aurelien Dantan, Department of Physics and Astronomy, Aarhus University, Denmark
Language: The PhD dissertation will be defended in English

The defence is public.
The PhD thesis is available for reading at the Graduate School of Natural Sciences/GSNS, Ny Munkegade 120, building 1521, 8000 Aarhus C