1. Hollow core planar waveguides and multilayers Prof. M. Skorobogatiy, review for the course ‘Introduction to Photonic Crystals’ École Polytechnique de Montréal Montréal, QC, Canada

2. 1 ~D~D T R I=1 R2R2 R3R3 R4R4 T D 2 / D TT TIR silica fiber D=10  m =1.55  m, loss=0.2dB/km T=10 -6 -10 -5 Hollow core planar waveguide, scaling relations REFLECTOR

3. 2 Metallic reflectors Simplest mirrors present thin layers of metals such as aluminum deposited on glass substrates. Choice of metals will determine reflection characteristics of a mirror. Aluminum is the cheapest and least expensive material with a coefficient of reflection of 88%-92% in the visible. More expensive is silver with reflectivity of 95%-99% even in the IR, while less than 90% in the blue and UV. Most expensive is gold with an excellent reflectivity of 98%-99% in the IR, while poor reflectivity below 550 nm. Metallic Reflector Omnidirectional reflection, high material loss in the IR 

4. 3 Losses of hollow metallic waveguides D=100  m; =1-10  m; T=10 -2 Losses=1-10 dB/m T R I=1 D REFLECTOR

5. 4 11 1 90 o 0 tan -1 (n h /n l ) p-pol s-pol Reflectance Contraste d’indice s’augmente Conventional Dielectric Mirrors Very low material absorption loss, strong dependence of reflection characteristics on the light polarization SiO 2 -air 0.04 AsSe-air 0.22 nlnl nhnh  Contraste d’indice s’augmente Dielectric reflectors Dielectric mirrors are characterised by very low absorption losses, but their reflection characteristics are strongly dependent of the angle of radiation incidence and polarization. For the s-polarized light reflectivity increases monotonically with an increase of an angle of incidence. However, for a p-polarised light reflectivity goes through zero at a so called Brewster angle.

6. 5 Losses of hollow dielectric waveguides D=100  m; =1-10  m; n c =1; n r =1.5 Losses TE =0.04-4 dB/cm T R I=1 D REFLECTOR ~D~D

7. 6 ARROW waveguides =1.55mm Losses TE =0.2 dB/cm

8. 7 ARROW multilayer waveguides

9. 8 D. Yin et al. 14 June 2004 / Vol. 12, No. 12 / OPTICS EXPRESS 2710 d c ~3.7 m  12m  Capillary 1 layer 2 layers 3 layers Sensor applications - putting the light where the analyte (gas) is Planar antiresonant reflecting optical (ARROW) waveguides, SiN/SiO 2 (2.1/1.46)

10. Omnidirectional reflectors OR high index contrast multilayers

11. 10 Te / polystyrene  normal  =0 o  =90 o EpEp EsEs Omnidirectional Dielectric Mirrors Reflection for all angles of incidence and polarizations Multilayer dielectric reflectors Omnidirectional reflection - for any incoming polarization and any angle of incidence radiation is completely reflected in a certain frequency band.

12. 11 Omnidirectional dielectric reflectors  normal  =0 o  =90 o EpEp EsEs

13. 12  normal  =0 o  =90 o EpEp EsEs Omnidirectional dielectric reflectors

14. 13  normal  =0 o  =90 o EpEp EsEs Omnidirectional dielectric reflectors When cladding index n c is increased beyond a critical value, omnidirectional reflectivity is lost.

15. Omnidirectional reflectors SURPRIZE !!! low index contrast multilayers

16. 15 All-polymer multilayers nlnl nhnh 

17. 16 Giant birefringence polymer multilayers

18. 17 Giant birefringence polymer guides