Current Issue : January - March Volume : 2015 Issue Number : 1 Articles : 4 Articles
Purpose. To evaluate to which extent individual Zernike terms can be corrected. Methods. Ablation time and fidelity was analysed\nusing different fluence levels (range 90ââ?¬â??2000 mJ/cm2) and aspheric ablation profiles.With optimal parameters, the extent to which\nindividual Zernike modes can be corrected was evaluated. Results. The range 188ââ?¬â??565 mJ/cm2 resulted as optimum fluence level\nwith an optimum proportion range 50%ââ?¬â??90% for high fluence. With optimal parameters, it corresponds to 2.4 s/D at 6mm OZ,\nwith fidelity variance of 53 ?m RMS, and average ablation error of 0.5 ?m for each location. Ablation simulation of coma Z[3,Ã?±1]\nshowed 98,4% accuracy and 98% fit quality; trefoil Z[3,Ã?±3], 99,9% accuracy and 98% fit quality; spherical aberration Z[4,0],\n96,6% accuracy and 97% fit quality; secondary astigmatism Z[4,Ã?±2], 97,9% accuracy and 98% fit quality. Real ablation on a flat\nplate of PMMA of coma Z[3,Ã?±1] showed 96,7% accuracy and 96% fit quality; trefoil Z[3,Ã?±3], 97,1% accuracy and 96% fit quality;\nspherical aberration Z[4,0], with 93,9% accuracy and 90% fit quality; secondary astigmatism Z[4,Ã?±2], with 96,0% accuracy and\n96% fit quality. Conclusions. Ablation of aspherical and customised shapes based upon Zernike polynomials up to the the 8th order\nseems accurate using the dual fluence concept implemented at the AMARIS platform....
We fabricated a high-efficiency infrared light emitting diode (LED) via dressed-photon-phonon (DPP) assisted annealing of a p-n\nhomojunctioned bulk Si crystal.The center wavelength in the electroluminescence (EL) spectrum of this LED was determined by\nthe wavelength of a CW laser used in the DPP-assisted annealing.We have proposed a novel method of controlling the EL spectral\nshape by additionally using a pulsed light source in order to control the number of phonons for the DPP-assisted annealing. In this\nmethod, the Si crystal is irradiated with a pair of pulses having an arrival time difference between them. The number of coherent\nphonons created is increased (reduced) by tuning (detuning) this time difference.ASi-LED was subjected toDPP-assisted annealing\nusing a 1.3 ?m (?v = 0.94 eV) CW laser and a mode-locked pulsed laser with a pulse width of 17 fs.When the number of phonons\nwas increased, the EL emission spectrum broadened toward the high-energy side by 200meV or more. The broadening towards\nthe low-energy side was reduced to 120 meV....
Modeling and simulating atmospheric turbulence in a controlled environment have been a focus of interest for scientists for decades.\nThe development of new technologies allows scientists to perform this task in a more realistic and controlled environment and\nprovides powerful tools for the study and better understanding of the propagation of light through a nonstatic medium such as\nthe atmosphere. Free space laser communications (FSLC) and studies in light propagation through the atmosphere are areas which\nconstantly benefit from breakthroughs in technology and in the development of realistic atmospheric turbulence simulators, in\nparticular (Santiago et al. 2011). In this paper, we present the results fromthe implementation of a phase only spatial light modulator\n(SLM) as an atmospheric turbulence simulator for light propagation in the short-wave infrared (SWIR) regime. Specifically, we\ndemonstrate its efficacy for its use in an FSLC system, at a wavelength of 1550 nm....
Progress of high-speed vertical cavity surface emitting lasers (VCSEL) operating around 980nm is reviewed. A special focus\nis on their applications for future short-reach optical interconnects, for example, in high-performance computers (HPC). The\nwavelength of 980nm has fundamental advantages for these applications and plays a significant role in VCSEL research today. The\npresent data rates of 980nm VCSELs exceed 40 Gbit/s, and excellent temperature stability has been reported. The major concepts\nleading to these impressive developments are presented...
Loading....