| Abstract [eng] |
In this work, optically-pumped semiconductor laser structures with InGaAs and GaAsBi quantum well active regions were grown and studied. InGaAs was chosen as a well-known semiconductor with mature technology, while GaAsBi was taken as a novel material for new generation NIR lasers. VECSELs combine main advantages of both, semiconductor and solid-state lasers, therefore are very attractive for various applications in photonics and optoelectronics. In the first part of the work, molecular beam epitaxy growth conditions were studied in order to obtain quantum well emission at chosen wavelengths of 1030 nm, 1064 nm and 1160 nm. It was found, that optimal growth temperature for InGaAs quantum wells is 560 oC, while in the case of GaAsBi QWs it is 370 oC. Furthermore, In/Ga BEP ratio of 0,93 and 1,225 and As/Ga BEP of 1,07 during MBE growth result in quantum wells, emitting around those target wavelengths. VECSEL structures with InGaAs and GaAsBi quantum well active regions were modelled and all other layers inside the structure (spacer, window, capping) were calculated. In these structures, 10 nm thick GaAsBi quantum wells with 5% of Bi were used in order to obtain emission wavelength of 1160 nm, while 7 nm thick InGaAs quantum wells with 23,5 and 26% of In resulted in emission wavelengths of 1030 nm and 1064 nm, respectively. The grown structures were characterized by reflectance and room temperature PL measurements. Quantum well photoluminescence peaks were well-matched with resonant frequencies of VECSEL structures, which resulted in huge increase in emission. An attempt to obtain lasing from these structures will be made by improving the optical pumping setup, optimizing heat management in the structure and forming antireflective coatings. |
