Hossein Masalehdan | University of Hamburg (original) (raw)
Address: Institute for Quantum Physics (IQP)
Luruper Chaussee 149
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Papers by Hossein Masalehdan
Advanced Energy Materials
In this paper we developed the Thermal transfer mechanism in the Carbon Nano-Tubes (CNTs) 15nm ch... more In this paper we developed the Thermal transfer mechanism in the Carbon Nano-Tubes (CNTs) 15nm channel length, we analyzed transfer phenomena by new methods of Modern Quantum Mechanics to distribute Dirac thermal equation in two dimensions when the structure's dimension is in the order of Broglie wave length, and it has shown completely that depending on the dynamics of the heat that carriers scattering the damped or oscillated temperature field can be generated in CNTs. When the laser pulse generates relativistic electrons the cross section for the generation of electron-positron pairs is equal to the Thomson cross section.
"A 1D photonic crystal structure contains 16 layers, 8 common dielectric layers ... more "A 1D photonic crystal structure contains 16 layers, 8 common dielectric layers and 8 layers with nonlinear medium, with an arrangement similar to the 5th generation, Thue–Morse multilayer is presented. The properties of photonics band gap, field distribution and optical multistability are investigated. On the band gap, 5 resonant modes is observed. On the behavior of output intensity versus input intensity around resonant frequencies, the multistability response observed. When the frequency of incident field is close to the resonant frequency, the threshold intensity of multistability is decreased. "
2010 17th Iranian Conference of Biomedical Engineering (ICBME), 2010
From the physical point of view, all known parameters for fs-laser induced optical breakdown to c... more From the physical point of view, all known parameters for fs-laser induced optical breakdown to cut corneal tissue are beneficial for the low pulse energy high frequency femtosecond surgical laser like Ziemer's Femto LDV. The used fs-laser oscillator makes the Femto LDV compact and robust, delivers low pulse energy at high frequencies and has an unreached preciseness due to the high focussing optics very close to the treated area. The special feature of the low energy pulses can reduce bubble formation during the cutting process. The smaller the bubbles, the more precise the cut can be positioned, especially with respect to Sub Bowman Keratomileusis (SBK).
2010 17th Iranian Conference of Biomedical Engineering (ICBME), 2010
Currently there is considerable interest in correcting the higher-order optical aberrations of th... more Currently there is considerable interest in correcting the higher-order optical aberrations of the human eye. Present-day laser eye surgery techniques like PRK and LASIK correct only defocus and astigmatism, which are 2 nd order aberrations. Surgically correcting the additional higherorder aberrations could extend the limits of human vision beyond 20/20. In addition, this type of capability could be used to eliminate the higher-order aberrations that may have been caused by a prior surgical procedure. These induced aberrations are responsible for the glare, halos, and other visual defects that have been reported by some eye surgery patients.
Biomedical Optics and 3-D Imaging, 2010
Optics and Lasers in Engineering, 2011
The European Physical Journal Applied Physics, 2011
The interaction of the near IR femtosecond laser pulses with photochromic glass sample is investi... more The interaction of the near IR femtosecond laser pulses with photochromic glass sample is investigated. Two different types of microstructures due to the optical properties modification of the sample are observed at the irradiated regions with single laser pulses. Laser fluence and shot number dependency of the structures are investigated. The optical transmission of irradiated areas is analyzed spectroscopically.
The European Physical Journal D, 2010
Optical and Quantum Electronics, 2009
Acta Physica Polonica A, 2013
The eect of linear absorptions on conversion eciency of the fundamental radiation to the second h... more The eect of linear absorptions on conversion eciency of the fundamental radiation to the second harmonic wave in a layered structure is investigated under intensity constant approximation. Behaviour of the conversion eciency after each layer, up to third layer, is graphically illustrated.
The European Physical Journal Applied Physics, 2015
Advanced Energy Materials
In this paper we developed the Thermal transfer mechanism in the Carbon Nano-Tubes (CNTs) 15nm ch... more In this paper we developed the Thermal transfer mechanism in the Carbon Nano-Tubes (CNTs) 15nm channel length, we analyzed transfer phenomena by new methods of Modern Quantum Mechanics to distribute Dirac thermal equation in two dimensions when the structure's dimension is in the order of Broglie wave length, and it has shown completely that depending on the dynamics of the heat that carriers scattering the damped or oscillated temperature field can be generated in CNTs. When the laser pulse generates relativistic electrons the cross section for the generation of electron-positron pairs is equal to the Thomson cross section.
"A 1D photonic crystal structure contains 16 layers, 8 common dielectric layers ... more "A 1D photonic crystal structure contains 16 layers, 8 common dielectric layers and 8 layers with nonlinear medium, with an arrangement similar to the 5th generation, Thue–Morse multilayer is presented. The properties of photonics band gap, field distribution and optical multistability are investigated. On the band gap, 5 resonant modes is observed. On the behavior of output intensity versus input intensity around resonant frequencies, the multistability response observed. When the frequency of incident field is close to the resonant frequency, the threshold intensity of multistability is decreased. "
2010 17th Iranian Conference of Biomedical Engineering (ICBME), 2010
From the physical point of view, all known parameters for fs-laser induced optical breakdown to c... more From the physical point of view, all known parameters for fs-laser induced optical breakdown to cut corneal tissue are beneficial for the low pulse energy high frequency femtosecond surgical laser like Ziemer's Femto LDV. The used fs-laser oscillator makes the Femto LDV compact and robust, delivers low pulse energy at high frequencies and has an unreached preciseness due to the high focussing optics very close to the treated area. The special feature of the low energy pulses can reduce bubble formation during the cutting process. The smaller the bubbles, the more precise the cut can be positioned, especially with respect to Sub Bowman Keratomileusis (SBK).
2010 17th Iranian Conference of Biomedical Engineering (ICBME), 2010
Currently there is considerable interest in correcting the higher-order optical aberrations of th... more Currently there is considerable interest in correcting the higher-order optical aberrations of the human eye. Present-day laser eye surgery techniques like PRK and LASIK correct only defocus and astigmatism, which are 2 nd order aberrations. Surgically correcting the additional higherorder aberrations could extend the limits of human vision beyond 20/20. In addition, this type of capability could be used to eliminate the higher-order aberrations that may have been caused by a prior surgical procedure. These induced aberrations are responsible for the glare, halos, and other visual defects that have been reported by some eye surgery patients.
Biomedical Optics and 3-D Imaging, 2010
Optics and Lasers in Engineering, 2011
The European Physical Journal Applied Physics, 2011
The interaction of the near IR femtosecond laser pulses with photochromic glass sample is investi... more The interaction of the near IR femtosecond laser pulses with photochromic glass sample is investigated. Two different types of microstructures due to the optical properties modification of the sample are observed at the irradiated regions with single laser pulses. Laser fluence and shot number dependency of the structures are investigated. The optical transmission of irradiated areas is analyzed spectroscopically.
The European Physical Journal D, 2010
Optical and Quantum Electronics, 2009
Acta Physica Polonica A, 2013
The eect of linear absorptions on conversion eciency of the fundamental radiation to the second h... more The eect of linear absorptions on conversion eciency of the fundamental radiation to the second harmonic wave in a layered structure is investigated under intensity constant approximation. Behaviour of the conversion eciency after each layer, up to third layer, is graphically illustrated.
The European Physical Journal Applied Physics, 2015
In this paper, we use Zernike Polynomials Model (ZPM) that is a very suitable Model for eye optic... more In this paper, we use Zernike Polynomials Model (ZPM) that is a very suitable Model for eye optical aberrations that can be potentially cured with femtosecond laser surgery. From our previous studies, ZPM can describe the wave aberration function for different kinds of pupil patterns and we show its abilities upto 6th orders of aberrations such as Coma, Trefoil, different grades of spherical aberrations and secondary aberrations. These days, optical corrections surgery methods such as LASIK, PRK can only be used for the first and the second orders of aberrations and they can give patients good clinical vision. However, Cornea topography shows that aberrations in higher orders after the first surgery become very problematic for patients and they need the second surgery which might not be possible because of having a thin corona. We calculate point spread function (PSF) and Modulation Transfer Function (MTF) to measure wave generations in optical surface. The OTF is calculated by using the Fourier transform of the PSF and finally we have our final model for different orders of aberrations. By exchanging the angles and changing the parameters, the program becomes suitable for different laser surgery machines. At last, by converting the cornea surface topography with ZMP, every pixel can easily be tracked (RMS wavefront error 'is in microns', and wavelength ' is in nanometers') and be corrected with laser shots. The advantage of this method is its ability to correct the damaged areas point by point which leads to the fact that patients will have high vision. It can decrease laser machining time which decreases the most unwanted side effects.