Accession Number : ADA524885


Title :   Enhanced Ultrafast Nonlinear Optics With Microstructure Fibers And Photonic Crystals


Descriptive Note : Final rept. 30 Jun 2003-30 Jun 2004


Corporate Author : MOSCOW STATE LOMONOSOV UNIV (RUSSIA)


Personal Author(s) : Zheltikov, Aleksei


Full Text : http://www.dtic.mil/get-tr-doc/pdf?AD=ADA524885


Report Date : JUL 2004


Pagination or Media Count : 13


Abstract : A broad class of nonlinear-optical phenomena enhanced in microstructure and photonic-crystal fibers has been studied both experimentally and theoretically as a part of this project. Hollow-core photonic crystal fibers capable of transporting sub-100-fs pulses of Ti: sapphire laser radiation in one of their transmission peaks centered around 800 nm have been designed and demonstrated. These fibers are shown to enhance self-phase modulation of submicrojoule 100-fs Ti: sapphire laser pulses, allowing a spectral bandwidth of 35 nm to be achieved with an 8-cm PCF sample. Two cascaded hollow-core photonic-crystal fibers with slightly shifted, but still overlapping transmission peaks are shown to function as an optical diode for ultrashort laser pulses. Submicrojoule 100-fs Ti: sapphire laser pulses with a spectrum falling within the passband of one of the fibers, but outside the passband of the second fiber, experience spectral broadening due to self-phase modulation in the first fiber. A part of this selfphase- modulation-broadened spectrum is then transmitted through the second fiber. Identical short pulses propagating in the opposite direction are blocked by the second fiber with a shifted passband. A forward-to-backward signal ratio exceeding 40 is achieved with the created photonic-crystal fiber diode for 0.9- J, 100-fs pulses of 800-nm Ti: sapphire laser radiation. Self-phase-modulation-induced spectral broadening of laser pulses in air-guided modes of hollow photonic-crystal fibers (PCFs) is shown to allow the creation of fiber-optic limiters for high-intensity ultrashort laser pulses. The performance of PCF limiters is analyzed in terms of elementary theory of self-phase modulation. Experiments performed with 100-fs microjoule pulses of 800-nm Ti: sapphire laser radiation demonstrate the potential of hollow PCFs as limiters for 10-MW ultrashort laser pulses and show different PCF modes.


Descriptors :   *NONLINEAR OPTICS , *PHOTONIC CRYSTALS , PULSED LASERS , SAPPHIRE , RUSSIA , SHORT PULSES , MICROSTRUCTURE , FIBER OPTICS , LASER BEAMS


Subject Categories : ELECTRICAL AND ELECTRONIC EQUIPMENT
      LASERS AND MASERS
      FIBER OPTICS AND INTEGRATED OPTICS


Distribution Statement : APPROVED FOR PUBLIC RELEASE