Abstract: In this paper， KDy（WO₄）₂（KDW） crystal with a size of 40 mm × 40 mm × 15 mm was successfully grown by top-seeded solution growth （TSSG） method. The crystal structural， optical quality， thermal properties， laser induced damage threshold and magneto-optical properties of KDW crystal were comprehensively studied. The rocking curve shows that the full width at half-maximum of KDW （020） wafer is 0.071 2°， indicating that the crystal has good crystal quality. The transmittance curve shows that the KDW （020） wafer has a high transmittance in the visible-near infrared band. The results of single crystal X-ray diffraction （SCXRD） refinement show that KDW crystal belongs to monoclinic I2/a space group， and ［DyO₈］， ［WO₆］ and ［KO₁₀］ groups constitute the crystal skeleton. The ［WO₆］-related vibration mode in Raman spectra matches the monoclinic KRe（WO₄）₂ system.Thermal tests indicate that the thermal conductivity， thermal diffusion coefficient and specific heat capacity of KDW crystal at 298 K are 3.792 W/（m·K）， 1.692 mm²/s and 0.307 J/（g·K）， respectively. The laser induced damage threshold of KDW （020） wafer is 745.1 MW/cm² at 1 064 nm and 10 ns. Based on the extinction method， the Verdet constants of KDW crystal at 405， 532 and 635 nm are -208.30， -82.17 and -54.01 rad/（m·T）， respectively， and the corresponding magneto-optical figure of merit （FOM） are 768.21， 615.77 and 412.52（°）/T， respectively. This study shows that KDW crystal has excellent thermal/damage resistant properties and good visible Faraday rotation ability， and is a competitive magneto-optical crystal in visible-near infrared band.

Key words: magneto-optical crystal; KDW; tungstate; TSSG method; Verdet constant; crystal growth