Terahertz pulses propagation in microstructured photonic crystal

fibers

Jessienta Anthonya*

Rainer Leonhardta, Maryanne C. Largeb, Alexander Argyrosb, Sergio Leon-Savalb

NZIP Conference 2011

a Physics Department, The University of Auckland, Auckland, NEW ZEALAND

b Institute of Photonics and Optical Science (IPOS), School of Physics, The University of Sydney, Sydney NSW, AUSTRALIA

jant012@aucklanduni.ac.nz

Outline

• Introduction to terahertz (THz)• How to generate & detect THz?• Guiding the invisible THz in THz

PCFs• Summary

What is THz?

• THz = Far-infrared = sub millimeter• Frequency range = .1 to 10 THz

( ~ 3 cm - .3 m)• Transparent to most materials:

Plastics, clothing...• Reflected by metals, absorbed by

water

Experimental Method

• Coherent, pulsed THz-TDS setup

THz symmetric-pass lens design : Lo & Leonhardt, Opt. Expr. 16, 15991 (2008) 

THz Photonic Crystal Fibers• Solid core PCFs: High index guiding

HDPE tube + rings PCF

Han et. al,APL 80, 2634 (2002)

Large mode area Topas® PCF

Nielsen et. alOpt. Expr. 17, 8592

(2009)

Zeonex® PCFAnthony et. al

JOSA B 28, 1013 (2011)

THz Photonic Crystal Fibers• Solid core PCFs: High index guiding

•

• Air core PCFs: Photonic bandgap guidance

HDPE tube + rings PCF

Han et. al,APL 80, 2634 (2002)

Large mode area Topas® PCF

Nielsen et. alOpt. Expr. 17, 8592

(2009)

Zeonex® PCFAnthony et. al

JOSA B 28, 1013 (2011)

Ring-structured BraggPMMA PBGFPonseca et. al

Opt. Lett. 33, 902 (2008)

Kagome (‘Eye of the basket’)PMMA MOFsAnthony et. al

Opt. Expr. 19, 18470 (2011)

THz Photonic Crystal Fibers• Solid core PCFs: High index guiding

•

• Air core PCFs: Photonic bandgap guidance

HDPE tube + rings PCF

Han et. al,APL 80, 2634 (2002)

Large mode area Topas® PCF

Nielsen et. alOpt. Expr. 17, 8592

(2009)

Zeonex® PCFAnthony et. al

JOSA B 28, 1013 (2011)

Ring-structured BraggPMMA PBGFPonseca et. al

Opt. Lett. 33, 902 (2008)

Kagome (‘Eye of the basket’)PMMA MOFsAnthony et. al

Opt. Expr. 19, 18470 (2011)

Zeonex Microstructured Fibers

• High index guidanceModified total internal reflection

• Material: Zeonex (n = 1.52; = .13 cm-1)

• Core diameter = 400 m;air filling fraction = 82%

Results

• Temporal evolution of fundamental mode in Zeonex fibers

Results

• Measured loss limited only to material loss, negligible waveguide loss.

Results

• Normal, low dispersion THz propagation as confirmed by model & simulations

Kagome Microstructured Fibers

• PMMA rings in a triangular pattern• Fabrication: Stack-and-draw preform• Core diameters: 1.8 mm, 2.2 mm• Strut thickness: ~55 m, ~65 m

Guiding mechanism of kagome

• Inhibited coupling: Minimized mode overlap of core mode and cladding mode

• Loss characteristics: Determined by the strut thickness and index contrast

• Spectral properties similar to ARROW*: High transmission loss due to modes supported by cladding solid struts

Anti-Resonance Reflecting Optical Waveguide[Litchinitser et al., Opt. Expr. 11, 1243 (2003)]

Results

• Temporal evolution of guided THz pulses in Kagome fibers

Results

• Kagome measured attenuation coefficient: < 0.6 cm-1

Results

• Kagome mode scans: Fundamental mode only

Results

• Kagome mode scans: Fundamental mode only, good agreement with simulations

Results

• Phase index: Below unity, no coupling to modes in Kagome cladding

Results

• Wider transmission window; low dispersion THz propagation

Summary

Introduction to THz, THz-TDS, THz PCFs

High index guiding in Zeonex PCFInhibited coupling in kagomeCharacterize PCFs with THz-TDSDiscussion of results: Loss spectra,

fundamental mode air-guidance.PCFs open avenue towards low loss

THz waveguides

Thank you