Hole burning spectroscopy of R′ aggregate color centers in polycrystalline LiF thin films using a GaAlAs diode laser

The first spectroscopic measurements of R′ aggregate color centers contained in polycrystalline LiF hosts are reported. The inhomogeneous and homogeneous widths of the 830-nm zero phonon line are measured by conventional grating spectroscopy and by photochemical hole burning spectroscopy using a current tuned GaAlAs diode laser with 3-mW output power. An extensive photochemical hole burning comparison between single and polycrystalline samples is presented.