Dy3+‐ and Er3+‐codoped YBr3 upconversion phosphor for detection of 1.3‐μm band infrared light

The efficient upconversion of 1.3-μm infrared light to visual light was investigated using YBr3: Dy3, Er3+ fluorescent material. When the fluorescent material with an optimum composition (2DyBr3: 20ErBr3: 78YBr3) was illuminated with 1.3-μm laser beam from a semiconductor laser (LD 5 mW), the intensities of the colors red (Er3+: 4F9/2 → 4I15/2 radiation transition) and green (Er3+: 4S3/2 → 4I15/2 radiation transition) emitted from the fluorescent material were about 170 and 60 times stronger, respectively, than those from chloride-based fluorescent material. When this fluorescent material is illuminated by collimated LD beam with power higher than 1 mW, it continuously emits visual light (yellow) without preexcitation. Therefore, 1.3-μm infrared light can be detected visually under room light. This bromide-based fluorescent material is stable when it is packaged in a sealed dry atmosphere and its high efficiency wavelength upconversion characteristic is maintained over a year. In this material, Dy3- acts as an absorption center of 1.3μm light (6H15/2 → 6H9/2 transition) and fluorescence is caused by energy transmission to the Er3+ light-emission center due to suppression of multiphonon relaxation from the Dy3+ excitation level. The high efficiency also results because a large number of Dy3+ absorption centers can be added due to the low energy-transfer efficiency in the bromide-based material. This paper also describes the wavelength conversion process and the reverse transfer process from Er3+ to Dy3+.

[1]  Junichi Ohwaki,et al.  Efficient 1.5 µm to Visible Upconversion in Er3+-Doped Halide Phosphors , 1994 .

[2]  H. Kuroda,et al.  Mechanism and Controlling Factors of Infrared-to-Visible Conversion Process in Er3+ and Yb3+-Doped Phosphors , 1972 .

[3]  G. F. Sá,et al.  1.5 μm high detectivity quantum counter by energy transfers in diode pumped glassceramics , 1985 .

[4]  F. Auzel,et al.  Materials and devices using double-pumped-phosphors with energy transfer , 1973 .

[5]  S. P. Keller,et al.  Studies on Some Infrared Stimulable Phosphors , 1957 .

[6]  J. Ohwaki,et al.  1.3 μm to visible upconversion in Dy3+‐ and Er3+‐codoped BaCl2 phosphor , 1994 .

[7]  J. Ohwaki,et al.  Infrared to Visible Upconversion of Er3+ Doped in a Chloride Matrix , 1992 .

[8]  H. Moos,et al.  MULTIPHONON ORBIT-LATTICE RELAXATION OF EXCITED STATES OF RARE-EARTH IONS IN CRYSTALS. , 1968 .

[9]  D. L. Dexter,et al.  Phonon Sidebands, Multiphonon Relaxation of Excited States, and Phonon-Assisted Energy Transfer between Ions in Solids , 1970 .

[10]  R. A. Hewes.  Multiphoton excitation and efficiency in the Yb3+-R.E.3+ (Ho3+, Er3+, Tm3+) systems , 1970 .

[11]  J. Ohwaki,et al.  High‐efficiency infrared‐to‐visible upconversion of Er3+ in BaCl2 , 1993 .

[12]  Robert A. Satten,et al.  Spectra and energy levels of rare earth ions in crystals , 1968 .

[13]  J. Ohwaki,et al.  New efficient upconversion phosphor BaCl/sub 2/:Er under 1.5 mu m excitation , 1993 .

[14]  D. Kahng,et al.  Electroluminescence of ZnS Lumocen Devices Containing Rare‐Earth and Transition‐Metal Fluorides , 1969 .

[15]  Y. Mita.  Detection of 1.5‐μm wavelength laser light emission by infrared‐excitable phosphors , 1981 .