Browsing by Author "S. Pipatsart"

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    Geometrically distributed one-dimensional photonic crystals for all angle optical filters
    (2012) C. Teeka; S. Pipatsart; P.P. Yupapin; P.P. Yupapin; Nanoscale Science and Engineering Research Alliance (n'Sera), Faculty of Science, King Mongkut's Institute of Technology, Ladkrabang, Bangkok 10520, Thailand; email: kypreech@kmitl.ac.th
    We present the general formulation of light reflection using a series of one-dimensional (1D) photonic crystals (PCs) with different periods, which is made of nonabsorptive materials of any refractive indices.To have a large bandgap, the spectral range of reflection, the periods of 1D PCs must be distributed in a geometrical progression with a common ratio, r, smaller than a maximum value of r c. In this letter, the exact expressions for rc, the bandgap to mid gap ratio of the PC heterostructure and the minimum number of PCs to achieve the desired range of bandgap in single and all angles of incidence have been presented. The proposed method can be used to design the optical filters for vast range of applications such as ultraviolet (UV) filters (i.e., sunglasses, eye safety glasses, UV photography filters) and visible light filters. © 2012 Wiley Periodicals, Inc.
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    SOLITON SPIN in AN ADD-DROP OPTICAL FILTER for LONG DISTANCE SPIN TRANSPORT
    (World Scientific Publishing Co. Pte Ltd, 2012) C. Teeka; M.S. Aziz; S. Pipatsart; K. Srinuanjan; J. Ali; P.P. Yupapin
    A new concept of an optical spin generation using bright and dark soliton conversion behaviors within a modified optical add-drop filters known as a PANDA ring resonator is proposed. The orthogonal solitons can be formed randomly within the system and detected simultaneously at the output ports. Under the resonant condition, the orthogonal solitons corresponding to the left-hand and right-hand solitons (photons) can be generated. Whenever a photon is absorbed by an object, an angular momentum of either + _ or - _ is imparted to the object, in which two possible spin states known as soliton spins are exhibited. Many soliton spins, i.e., many particles, dynamic spin and long distance spin transport using the proposed design are also discussed. © 2012 World Scientific Publishing Company.