Probing non-radiative quantum relaxation in light-matter interaction with an optical fiber Bragg grating technique

Abstract: While optical fiber Bragg gratings (FBGs) have been widely used in sensing applications, their potential for investigating quantum processes involved in light-matter interactions remains unexplored. Here, we experimentally demonstrate a method of probing photon-induced non-radiative thermal relaxation in nanomaterials using the FBG technique. In response to photons of different excitation wavelengths, the FBG with nanomaterials present on its cladding exhibits distinct Bragg wavelength shifts, reflecting the extent of vibronic transitions, molecular absorption characteristics, and non-radiative thermal release. Moreover, the proposed method provides insights into photothermal localization and photothermal information from modulation of the Bragg spectral splitting. The photon-induced non-radiative thermal relaxation across different materials, molecular concentrations, and excitation intensities demonstrates that the FBG technique can probe localized photothermal relaxation at the micron scale under low optical excitation. These findings establish FBGs as a versatile platform for studying quantum phenomena in light-matter interactions and open new opportunities in molecular spectroscopy, biomedical diagnostics, and photothermal characterization.

Event Details
Title: Probing non-radiative quantum relaxation in light-matter interaction with an optical fiber Bragg grating technique
Date: June 11, 2026 at 11:00 AM
Venue: ESB 244 / Google Meet (https://meet.google.com/rcp-uzwc-vvf)
Speaker: Ms. Sweta Rath (EE20D066)
Guide: Dr. Shivananju B N
Type: PHD seminar