Introduction

Ytterbium Doped Calcium Gadolinium Aluminate (Yb:CaGdAlO₄ or Yb:CALGO) is a promising new laser gain material which possess several important advantages. The crystal structure of CALGO is tetragonal. When it is pumped at 979 nm under pi configuration, we can get broad emission spectra from 994 nm to 1050 nm in theta configuration. This implies a very low quantum defect (down to 1.5%) and gives a good expectation of obtaining ultra-fast pulse. In addition, Yb:CALGO also has a thermal conductivity of up to k=6.7 W/m/K, making it suitable for high-power laser applications.

CASTECH’s Yb:CaGdAlO₄ is featured by

 • High absorption coefficient @ 979 nm

 • High stimulated emission cross section

 • Low laser threshold

 • Extremely low quantum defect

 • Broad output at 994-1050 nm

 • High slope efficiency with diode pumping (up to 55%)

 • Various Yb-doping concentration

Applications

• Over 5.5W output power is obtained by 23W incident pumping diode laser with 10% output coupler.

• Output power as high as 12.5W and 94fs pulses for 28W pumping power was reported. 

Basic Properties                                                                                                                 

Specifications of Yb: CaGdAlO₄ crystal from CASTECH