We report on a distributed-feedback (DFB) color center laser based on N2 centers in KCl. A periodic grating with fringe spacings as fine as 440 nm was produced by means of a two-photon coloration process using two interfering beams. Coloration and photoaggregation processes and the DFB laser action can be availed by the fourth- and second-harmonic and the fundamental lines of a Q-switched Nd:YAG laser, respectively. The linewidth of the DFB output is less than 0.3 nm in the spectrally important 1300 nm region.

Ag-activated phosphate glass, which is the most commonly known radiophotoluminescent (RPL) material, has the capability to operate not only dosimeters but also two-and three-dimensional (2D and 3D) dose imaging detectors in the same host. This passive detector is based on radiation-induced, optically active nano-scale defects. In this work, the transient-state optical properties of the blue and orange RPL were investigated using a time-resolved spectrum technique for 137 Cs and 60 Co gamma-ray-irradiated Ag-activated phosphate glass. Specifically, the blue RPL intensity with a decay time of 5 ns as a function of the depth at the vicinity of the surface was systematically examined to clarify an accurate dose distribution within the glass. Moreover, a feasibility study into the use of an RPL Ag-activated phosphate glass detector for fluorescent nuclear track imaging was demonstrated using a confocal fluorescence image microscope for the first time.

A disk-type two-and three-dimensional (2D, 3D) X-ray dose imaging detector was developed based on the radiation-induced silver (Ag)-related species in Ag-activated phosphate glass. This luminescent detector is based on the blue and orange radiophotoluminescence (RPL) phenomena. A comparative study of the steady-and transient-state optical properties of blue and orange RPL, such as the time-resolved luminescence spectra and the RPL decay curves, was performed. In addition, the combination of a confocal optical detection system with a transparent glass detector enables 3D reconstruction through the stacking of dose images collected at different depths within the material. The capabilities of this detector for 2D and 3D dose imaging applications are discussed. Keywords Research Highlights> A disk-type 2D and 3D dose imaging detector based on RPL was developed.> The steady-and transient-state properties of the blue and orange RPL were presented.> The RPL detector is useful for fluorescent nuclear track detection.2