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Electronic structure and optical properties of the Ce3☎ in YAG has been investigated by standard spectroscopy (photoluminescence, absorption and excitation spectra) and high pressure spectroscopy. The bandshape of the emission spectrum for different pressures has been analyzed and influence of pressure on energy of the 5d1 states and the electron-lattice coupling have been determined. The significant red shift of the peak of the emission band (the respective pressure coefficient has been equal to—12cm−1/kbar) has been obtained. The shift has been understood by taking into account pressure induced increase of the 5d1 level splitting and increase of the electron-lattice coupling strength.

0.01-0.03 wt% Cr-doped 3CaO-Ga 2 O 3 -3GeO 2 glasses were prepared by a standard high-temperature synthesis method. We have studied ambient-pressure photoluminescence (PL) excitation spectra and high-pressure PL spectra of Cr ions in the glasses. The spectra indicated that Cr ions are very inhomogeneously dispersed in the glass matrix. The PL spectra of bulk samples at ambient conditions consisted of a narrow band (∼14,480 cm m 1 ) with a band width of ∼90 cm m 1 , a broad high-energy band (∼12,700 cm m 1 ) with a band width of ∼1700 cm m 1 , and a broad low-energy band (∼10,500 cm m 1 ). High-pressure PL results have provided the unique opportunity for the assignment of the three PL bands. The narrow band (∼14,480 cm m 1 ) is attributed to the 2 E M 4 A 2 transition of Cr 3+ in a high-field. The broad high-energy band (∼12,700 cm m 1 ) is attributed to a phonon sideband of the 2 E M 4 A 2 transition. The broad low-energy band (∼10,500 cm m 1 ) is attributed to a possible partly Cr 3+ or Cr 5+ centers tha...

High pressure luminescence spectroscopy is used to distinguish three principle Cr 3+ sites in LiTaO 3 . We tentatively assign the sites to Cr 3+ ions in Li + lattice sites that differ with respect to charge compensation. By fitting theoretical luminescence lineshapes to measured emission spectra, we are able to estimate the pressure shifts of the 4 T 2 and E states and the crystal field distribution for each Cr 3+ site.

The effect of pressure on the luminescence spectrum of the weak field system Cr3+ : LiTaO3 is presented. By using pressure to induce a low to high crystal field strength transition, we demonstrate the ability of pressure to identify distinct dopant bonding environments in luminescent materials.