Analysis of the Pump Wavelength Dependence of a 1060-nm VECSEL

We have developed an optically pumped infrared 1060-nm vertical-external-cavity surface-emitting laser for an application as a frequency doubled green laser in mobile projectors. The efficiency has been investigated as a function of pump wavelength and a differential efficiency η_diff of 50% has been demonstrated using an 808-nm pump laser source. The usage of a longer pump wavelength decreases the quantum defect and increases the differential efficiency to over 52%. The pump light absorption in the chip is investigated as a function of pump wavelength and absorber thickness. A thicker absorber layer enables the usage of a longer pump wavelength and hence reduces the quantum defect further.