Search for Ionization-Induced Modulation of Light Polarization for a New Direction to Improve Time Resolution of PET

In this work, we study whether ionizing radiation can induce a small component of non-polarized light in a cross-polarizer setup, where usually no light transmission would occur. Such ionization-induced modulation of polarization occurs at a sub-picosecond time scale, which could be exploited for fast timing applications, such as time of flight in positron emission tomography. We demonstrate the feasibility of this approach using ionization produced from a laser diode in high Z, high-density crystals. Results indicate that the signal strength, quantified by induced cross-polarized light due to ionization from 20 MHz UV pulses in BSO is 10× higher than that in CdTe.