We investigate in detail the effect of energy-transfer up-conversion (ETU) and excited-state absorption

(ESA) in diode-end-pumping quasi-three-level Nd:GdVO4 lasers. The energy levels of Nd:GdVO4

crystals and the rate equation involving ETU and ESA effects are presented. The results of simulation

show that the ETU effect is important in quasi-three-level lasers and can provide heating approximately

two times higher than that induced by the ESA. Moreover, the relationship between the incident pump

power and the 912 nm output power was simulated taking into account the ESA; a comparison with

experimental data is also presented.

As a result, we conclude that the ESA plays an important role in

the high-power pumping field; the estimated equivalent cross-section _ESA = (1.0 ± 0.5) · 10？20 cm2.