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Nonlinear Wave Propagation in Photonic Band Gap Materials

Thesis Info

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Author

Zulfiqar Ali, Munazza Zulfiqar

Program

PhD

Institute

University of the Punjab

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2008

Thesis Completion Status

Completed

Subject

Physics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/254

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726763881

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This research work is concerned with the nonlinear wave propagation in photonic band gap (PBG) materials. Photonic band gap materials are artificial periodic structures that exhibit bands and gaps for the propagation of light in certain frequency ranges depending on the periodicity of the structure. Nonlinear PBG materials can be defined as the periodic structures that have the ability to control light with light and produce a structural enhancement of nonlinear effects. The optical properties of such materials can show dramatic changes with the changing intensity of light. An interesting manifestation of nonlinear effects in these structures is the formation of gap solitons and the associated phenomenon of optical bistability. Promising applications for such phenomena include optical switches, logic gates, transistors etc. Recent theoretical and experimental studies have suggested the possibility of creating artificial metamaterials that can possess a negative real part of magnetic permeability and/or a negative real part of electric permeability and are known as double and single negative metamaterials (DNG, SNG). The main focus of the present study is to explore the new features of the nonlinear wave propagation due to the inclusion of double negative and single negative metamaterials in PBG structures. The conventional PBG structures are characterized by Bragg gaps whereas in PBG structures containing DNG and SNG metamaterials, mechanisms other than Bragg reflections can produce gaps such as the zero-n and the zero- φ eff gaps. The real advantage of these new gaps is the fact that these are relatively insensitive to the incident angle and disorders in the structures. iiIn the present work we have considered only one-dimensional structures. The transfer matrix approach and the characteristic matrix approaches are mainly used to study the wave propagation through these structures. We have also applied the Kronig-Penney delta function approach in one of our investigations. The electric field profiles for the zero-n gap soliton, zero-φ eff gap soliton and Bragg gap soliton are plotted and a comparison of their characteristics is made. Similarly the optical bistability curves for the one-dimensional structure containing alternate DNG and regular materials and containing SNG materials are also plotted. We have considered normal as well as oblique incidence. The properties of an angular gap in one-dimensional structures containing SNG layers are investigated. We have also investigated some defect structures. The properties of the resulting localized mode are studied. The results of the investigations are summarized at the end.
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مولانا عبدالباری ندوی

مولانا عبدالباری ندوی
افسوس ہے مولانا عبدالباری ندوی کاگزشتہ مہینہ ایک طویل علالت کے بعد ۸۲برس کی عمر میں ان کے وطن لکھنؤ میں انتقال ہوگیا۔ مولانا کے نہایت ذہین اور طباع ہونے کی دلیل اس سے زیادہ اورکیاہوسکتی ہے کہ ان کی اصل تعلیم قدیم طریقہ کے مطابق عربی اورفارسی کی تھی اور انگریزی غالباً ہائی اسکول تک پڑھی تھی لیکن اپنے ذاتی مطالعہ اورشوق سے انھوں نے انگریزی میں اتنی استعداد بہم پہنچائی کہ اولاً فلسفۂ یورپ اورثانیاًسائنس کا مطالعہ کرسکیں۔فلسفہ سے انھیں خاص مناسبت تھی، چنانچہ اس میں ایساکمال حاصل کیا کہ برکلےؔ،برگسانؔ اورڈیوڈ ہیوم پر انھوں نے کتابیں لکھیں اور ان کی بعض کتابوں کا اردو میں ترجمہ کیا اورنہ صرف یہ بلکہ عثمانیہ یونیورسٹی میں پہلے فلسفہ کے لیکچرر اورپھراس کے ریڈر مقرر ہوئے۔ اسی زمانہ میں سیرت النبیؐ مصنفہ مولانا سید سلیمان ندوی کی جلدسوئم کے قدیم ایڈیشن میں مرحوم نے معجزات پرجو ایک باب لکھا تھا وہ زبان وبیان اوراستدلال و استنتاج کے اعتبار سے ایک نہایت اہم مقالہ کی حیثیت رکھتاتھا۔
طبع سلیم اگر رہنما نہ توفرط ذہانت اورفلسفہ کے ساتھ انہماک وتوغل بسا اوقات گمراہی کا سبب ہوجاتے ہیں، چنانچہ مرحوم کے ساتھ یہی ہوا، زندقہ والحاد کا شکار ہوگئے۔ ایک مدت کے بعد جب مولانا تھانوی سے بیعت ہوئے تو فلسفہ کا ردعمل اس شکل میں ہوا کہ مذہب کارہبانی تصور غالب آگیا، غرض کہ وہ زمانہ میں ع
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زبانوں کی تہذیبی اہمیت عربی زبان و قرآن حکیم: اہمیت و کردار

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Molecular Characterization of Scabies Mite Sarcoptes Scabieivar. Hominis in Pakistan

Scabies is a human skin disease due to the burrowing ectoparasite Sarcoptes scabiei var. hominis resulting in intense itching and inflammation and manifesting as a skin allergy. Currently limited information is known about the genetic diversity of Sarcoptes scabiei mites in human and also little is known about the specific scabies molecules involved in the inflammatory and immunologic responses. Due to insufficient mite material and lack of in vitro propagation system for antigen preparation, scabies is a challenging disease to diagnose. To examine the extent of the genetic variation in the DNA sequences of Sarcoptes scabiei var. hominis, mites were collected from scabietic patients by visiting the dermatology clinics of private and government hospitals from different localities of Pakistan. Individual mite gDNA was first amplified using ITS-2 and 16S by PCR, however, later amplicons were sequenced directly. Sequence analysis of Pakistani isolates by mitochondrial 16S rRNA gene showed greater sequence variability with 0.451M average evolutionary divergence (AED) as compared to ITS-2 sequences having a level of 0.01M AED. Moreover, results derived from Neighbor-joining tree showed that ITS-2 sequences did not show any host segregation and geographical isolation, whereas 16S indicated presence of both host adapted and geographically segregated populations of S. scabiei. These results suggested that 16S rRNA appeared to be suitable for examining genetic diversity among human mite populations as compared to ITS-2. Moreover different varieties of Sarcoptes mites belonged to different host species and geographic regions recommended a common gene pool which represented existence of a single species. For allergen characterization, full-length S. scabiei tropomyosin (Sar s 10) was cloned xxiii and expressed in pET-15b and assessed for reactivity with IgE antibodies from human sera. IgE binding was observed to Sar s 10 with sera collected from crusted and ordinary scabies, House Dust Mite (HDM) positive and naive subjects and a diagnostic sensitivity of <30% was observed. S. scabiei paramyosin (Sar s 11) was cloned and expressed in pET-28a in three overlapping fragments designated as Sspara1, Sspara2 and Sspara3. IgE and IgG binding was observed to Sspara2 and Sspara3 antigens with sera collected from crusted and ordinary scabies, and HDM positive subjects but no binding was observed with sera collected from naive subjects. Sspara 2 displayed excellent diagnostic potential with 98% sensitivity and >90% specificity observed for IgE binding and 70% sensitivity for IgG. In contrast the diagnostic efficiency of Sspara 3, was 84% for IgE binding and 40% for IgG binding. In combination Sspara 2 and Sspara3 provided an IgE sensitivity of 98%. These results demonstrate the genus-specific scabies mite epitopesare able to detect IgE reactivity with high sensitivity. The developed ELISA represents a marked improvement for the clinical diagnosis of scabies and helps direct future development of a specific diagnostic tool for scabies. Keywords: Sarcoptes scabiei var. hominis, rDNA ITS-2, MtDNA-16S, Tropomyosin, Paramyosin, Recombinant, IgE, Diagnosis