Modeling the optical properties of hexagonal GaN

control of the optical properties of nanoparticles by laser fields

در این پایان نامه، درهمتنیدگی بین یک سیستم نقطه کوانتومی دوگانه(مولکول نقطه کوانتومی) و میدان مورد مطالعه قرار گرفته است. از آنتروپی ون نیومن به عنوان ابزاری برای بررسی درهمتنیدگی بین اتم و میدان استفاده شده و تاثیر پارامترهای مختلف، نظیر تونل زنی(که توسط تغییر ولتاژ ایجاد می شود)، شدت میدان و نسبت دو گسیل خودبخودی بر رفتار درجه درهمتنیدگی سیستم بررسی شده اشت.با تغییر هر یک از این پارامترها، در...

Improvement of Optical Properties in Hexagonal Index-guiding Photonic Crystal Fiber for Optical Communications

Waveguides with low confinement loss, low chromatic dispersion, and low nonlinear effects are used in optical communication systems. Optical fibers can also be employed in such systems. Besides optical fibers, photonic crystal fibers are also highly suitable transmission media for optical communication systems. In this paper, we introduce two new designs of index-guiding photonic crystal fiber ...

Optical properties of GaN pyramids

Picosecond time-resolved photoluminescence ~PL! spectroscopy has been used to investigate the optical properties of GaN pyramids overgrown on hexagonal-patterned GaN~0001! epilayers on sapphire and silicon substrates with AlN buffer layers. We found that: ~i! the release of the biaxial compressive strain in GaN pyramids on GaN/AlN/sapphire substrate led to a 7 meV redshift of the spectral peak ...

Optical properties of functionalized GaN nanowires

The influence of phonons on the optical properties of GaN

We comprehensively examine the importance of phonons on the optical properties of GaN. Using Raman and photoluminescence PL spectroscopies, the energies and linewidths of optic phonons, excitons, and discrete phonon sidebands PSBs are studied between 20 and 325 K. The temperature dependence of the A1 LO phonon energy and linewidth are described by a combined twoand three-phonon decay process. T...