# Fileset

[lat_fuse_sem4.pdf](https://mdr.nims.go.jp/filesets/e339547d-8b28-4e33-9a75-678ac6bdac26/download)

## Creator

[TODOROKI, Shin-ichi](https://orcid.org/0000-0003-3986-1900)

## Rights

In Copyright[In Copyright](http://rightsstatements.org/vocab/InC/1.0/)

## Other metadata

[Ultrahigh-speed videography of fiber fuse propagation: a tool for studying void formation](https://mdr.nims.go.jp/datasets/bf4df251-0294-4670-a954-3369546bfae8)

## Fulltext

UntitledLSuH1, ICONO/LAT 2005 (1)'&$%Ultrahigh-speed videography offiber fuse propagation:a tool for studying void formationShin-ichi TODOROKI (Xin�iqi Riiqeviq Todoroki)Advanced Materials Laboratory/NIMS JapanSlide 1'&$%Introduction Fiber fuse• Found in 1987(R.Kashyap & K.J.Blow)• Optical discharge runstoward the light source leaving periodic voids����Video~WHeat~1m/sSlide 2LSuH1, ICONO/LAT 2005 (2)'&$%OVERVIEWUltrahigh-speed videography of fiber fuse propagationVideographyHow was the fire-ball captured?Front voidWhat is left behind at the fire-ball’s position?Archaeology arheologi� ·考古学What is told from the photos of left behind?Slide 3'&$%VideographyHow was the fire-ball captured?SetupWhat is the trap like?MovieHow its behavior changed with the pumping power?AnalysisWhat is found out?Slide 4LSuH1, ICONO/LAT 2005 (3)'&$%Setup Shooting condition• 4µs/frame• 1µs-exposure with ND filters (×16)• 128×16 pixelsFiberLaser1480nmND filterSMF-289W1.5W...Zoom lensSlide 5'&$%Movie ����Movie 1• 4µs/frame• 1µs-exposure with ND filters (×16)• 128×16 pixelsSlide 6LSuH1, ICONO/LAT 2005 (4)'&$%FYI Current status of high-speed videographyTodoroki (ECOC 2004 PD)Todoroki (LAT 2005)Bufetov et al. (OFC 2005)4µs/frame Interval 128 or 70 µs/frame1µs Exposure 10µs+ ND filters + black illumination128×16 Pixels 1024×128����Movie 2Slide 7'&$%AnalysisSlide 8LSuH1, ICONO/LAT 2005 (5)'&$%Analysis Fusing speed & Void intervalSlide 9'&$%VideographyHow was the fire-ball captured?Setup1µs-exposure & x16 ND filters helped to catch it.MoviePumping with >2W makes intensity profile asymmetric.AnalysisAsymmetric optical discharge leaves periodic voids.Slide 10LSuH1, ICONO/LAT 2005 (6)'&$%Front voidWhat is left behind at the fire-ball’s position?PhotographyHow the samples were prepared?ComparisonWhat is related with the asymmetry of the discharge?Cavity sizeHow it changes with increasing the pumping power?Slide 11'&$%Photography Sample preparationFiberLaser1480nm SMF-289W1.5W...<100µs• observedas it isfocusedinsideSlide 12LSuH1, ICONO/LAT 2005 (7)'&$%ComparisonSlide 13'&$%Comparison←→LengthHWHM←→Slide 14LSuH1, ICONO/LAT 2005 (8)'&$%Comparison What we can say during quenching• Decay time of laser:=⇒ < 100µs (observed)=⇒ < one-void-formation(∼ 20µs)• Structural relaxation may occur,but expected to be small.=⇒ large∂η∂Tof silica glassSlide 15'&$%Cavity size←→Length∼9µmSlide 16LSuH1, ICONO/LAT 2005 (9)'&$%Front voidWhat is left behind at the fire-ball’s position?PhotographyPrepared by sudden power cut after fiber-fusing.ComparisonAsymmetric discharge leaves a tailed void.Cavity sizeVoid radius is constant & independent of input power.Slide 17'&$%ArchaeologyWhat is told from the photos of left behind?PeriodicityWhat comes into view considering periodicity?ReconstructionWhat is extracted from a series of photographs?MechanismWhy the regular voids look like bullets?Slide 18LSuH1, ICONO/LAT 2005 (10)'&$%Periodicity7W−→1480nmPeriodic voids−→One per 20µs←− Uniform velocitySlide 19'&$%Reconstruction• These are NOT in-situ• but seem that����Movie 3the void casts off its tail−→ one of regular voids• Assuming thateach structure issufficiently the sameas that before quenching,Slide 20LSuH1, ICONO/LAT 2005 (11)'&$%Mechanism Formation of a bullet(1)(2)(3)Distance from the top (4)(5)(6)(a)(b)(c)Temperature ViscosityOpt. Lett. submittedSlide 21'&$%Mechanism Tail is the source of periodic voids!Slide 22LSuH1, ICONO/LAT 2005 (12)'&$%ArchaeologyWhat is told from the photos of left behind?PeriodicityNormalized position is the key for sorting by time.ReconstructionExtended tail is casted off to be one of regular voids.MechanismOptical discharge pushes casted tail to make a bullet.Slide 23'&$%SUMMARYUltrahigh-speed videography of fiber fuse propagationVideography>2W-pump. ⇒ asymmetric discharge & periodic voidsFront voidAsymmetric discharge leaves a tailed void.ArchaeologyExtended tail is casted off to be one of periodic voids.Optical discharge pushes casted tail to make a bullet.Slide 24LSuH1, ICONO/LAT 2005 (13)'&$%Acknowledgement• Mr. Kazuhide HANAKA,Mr. Akira SAKAMAKI• Dr. Satoru INOUESlide 25