-
Investigation on the Optical Properties of Nonlinear Optical (NLO) Single Crystal: L-Valine Zinc Hydrochloride
Issue:
Volume 2, Issue 3, June 2014
Pages:
24-27
Received:
8 May 2014
Accepted:
20 May 2014
Published:
30 May 2014
Abstract: The development and encroachment of high technology, from transportation, computation to information is based on the availability of materials in the form of single crystals. With progress in crystal growth technology and characterization, organic, inorganic, semiorganic and organometallic materials having attractive nonlinear optical (NLO) properties are being discovered at rapid rate. NLO materials possess several attractive properties such as high NLO coefficient, high laser damage threshold, wide transparency range, high mechanical strength and thermal stability, which make the materials suitable for second harmonic generation (SHG) and other NLO applications. Single crystals of L-Valine zinc hydrochloride were grown by the slow evaporation technique. The single crystal X-ray diffraction analysis reveals that the crystal belongs to the monoclinic system. The optical absorption spectrum reveals the transparency of the crystal in the entire visible region and the cut off wave length has been found to be 210 nm. The optical band gap is found to be 5.91 eV. Optical constants such as the band gap (Eg), refractive index (n), reflectance (R), extinction coefficient (K) and the real (εr) and imaginary (εi) components of the dielectric constant and electric susceptibility (c) were determined from the UV-VIS-NIR absorption spectrum.
Abstract: The development and encroachment of high technology, from transportation, computation to information is based on the availability of materials in the form of single crystals. With progress in crystal growth technology and characterization, organic, inorganic, semiorganic and organometallic materials having attractive nonlinear optical (NLO) propert...
Show More
-
Whispering Gallery Modes Formation in Small Nanocavities Based upon Crossed Nanobeam Structures
Ahmadreza Daraei,
Atefeh Mohsenifard,
Mohammad Kafi Meibodi
Issue:
Volume 2, Issue 3, June 2014
Pages:
28-31
Received:
13 May 2014
Accepted:
29 May 2014
Published:
10 June 2014
Abstract: In this paper, we investigate conditions to form whispering gallery modes (WGMs) in small nanocavities (NCs) which are designed at the intersection area of couple of nanobeams (NBs) structures. Tapered air-holes at each branch of NBs have been employed as a part of mirror accompanied by curved-walls at cross junctions to form a small curved nanocavity. Simulations by finite element based commercial software, COMSOL Multiphysics 4.3 show that confined photonic modes are well established via WGM mechanism. Variation of modes wavelength and their field intensity profiles have been investigated. Quality factor, Q, as high as 198400 is obtained for a particular WGM at mode wavelength 1471.9 nm with computed modal volume as low as Vmod≈0.25(λ/n)3.
Abstract: In this paper, we investigate conditions to form whispering gallery modes (WGMs) in small nanocavities (NCs) which are designed at the intersection area of couple of nanobeams (NBs) structures. Tapered air-holes at each branch of NBs have been employed as a part of mirror accompanied by curved-walls at cross junctions to form a small curved nanocav...
Show More
-
OLED Display Technology
Issue:
Volume 2, Issue 3, June 2014
Pages:
32-36
Received:
22 May 2014
Accepted:
11 June 2014
Published:
30 June 2014
Abstract: OLEDs are solid-state devices composed of thin films of organic molecules that create light with the application of electricity. OLEDs can provide brighter, crisper displays on electronic devices and use less power than conventional light-emitting diodes (LEDs) or liquid crystal displays (LCDs) used today. OLEDs are made by placing thin films of organic (carbon based) materials between two conductors. When electrical current is applied, a bright light is emitted. The OLED materials emit light and do not require a backlight (unlike LCDs). Each pixel is a small light-emitting diode, in fact. OLEDs emit light they do not require a backlight and so are thinner and more efficient than LCD displays (which do require a white backlight).In this paper we investigate the characteristics of OLED.
Abstract: OLEDs are solid-state devices composed of thin films of organic molecules that create light with the application of electricity. OLEDs can provide brighter, crisper displays on electronic devices and use less power than conventional light-emitting diodes (LEDs) or liquid crystal displays (LCDs) used today. OLEDs are made by placing thin films of or...
Show More
-
Designing a High Speed 1310nm AlGaInAs/AlGaInAs VCSEL using MgO/Si Top DBR and GaInAsP/InP Bottom DBR
Arnob Islam,
Saiful Islam
Issue:
Volume 2, Issue 3, June 2014
Pages:
37-44
Received:
29 June 2014
Accepted:
7 July 2014
Published:
20 July 2014
Abstract: In this paper, a 1310nm intracavity structure Vertical Cavity Surface Emitting Laser (VCSEL) has been designed using quaternary compound material of AlGaInAs in both QW and barrier but with different composition. This choice has been made instead of choosing widely used GaInAsP/ InP, GaInAsN/ GaAs to gain some advantages. This combination has shown good band offset in the conduction band. Lattice matching has been obtained in the layers from the substrate up to the top contact layer except the quantum well (QW) layers where small amount of compressive strain of 1.55% has been used. From the substrate up to the top contact layer, fabrication can be done by epitaxial growth without any difficulty. Reduction in height by using 5 pairs of the top dielectric DBR mirror system of MgO/ a-Si is an attraction of this design which can be fabricated by evaporation technique. Dissipation in the bottom DBR due to current flow has been eliminated by using intracavity structure which also gave a way out for the current flow bypassing the dielectric top DBR. The active material compositions have been chosen to obtain a peak gain at 1310nm. The end result of this design is a top emitting VCSEL based on InP substrate using a different structure which is capable of producing 1310nm light output and which can be constructed easily using widely used epitaxial techniques mixed with the evaporation technique for the top DBR mirror system. The structure is suitable for use in optical ICs.
Abstract: In this paper, a 1310nm intracavity structure Vertical Cavity Surface Emitting Laser (VCSEL) has been designed using quaternary compound material of AlGaInAs in both QW and barrier but with different composition. This choice has been made instead of choosing widely used GaInAsP/ InP, GaInAsN/ GaAs to gain some advantages. This combination has shown...
Show More
