scholarly journals Phase-resolved pulse propagation through metallic photonic crystal slabs: plasmonic slow light

Author(s):  
Anja Schönhardt ◽  
Dietmar Nau ◽  
Christina Bauer ◽  
André Christ ◽  
Hedi Gräbeldinger ◽  
...  

We characterized the electromagnetic field of ultra-short laser pulses after propagation through metallic photonic crystal structures featuring photonic and plasmonic resonances. The complete pulse information, i.e. the envelope and phase of the electromagnetic field, was measured using the technique of cross-correlation frequency resolved optical gating. In good agreement, measurements and scattering matrix simulations show a dispersive behaviour of the spectral phase at the position of the resonances. Asymmetric Fano-type resonances go along with asymmetric phase characteristics. Furthermore, the spectral phase is used to calculate the dispersion of the sample and possible applications in dispersion compensation are investigated. Group refractive indices of 700 and 70 and group delay dispersion values of 90 000 fs 2 and 5000 fs 2 are achieved in transverse electric and transverse magnetic polarization, respectively. The behaviour of extinction and spectral phase can be understood from an intuitive model using the complex transmission amplitude. An associated depiction in the complex plane is a useful approach in this context. This method promises to be valuable also in photonic crystal and filter design, for example, with regards to the symmetrization of the resonances. This article is part of the themed issue ‘New horizons for nanophotonics’.

2014 ◽  
Vol 28 (03) ◽  
pp. 1450025
Author(s):  
YE LIU ◽  
BO FANG ◽  
LILI WANG ◽  
CHUN JIANG

In this paper, we propose a structure with cascaded two photonic crystal line-defect waveguides to reduce group velocity dispersion (GVD) of slow light. The width of the line-defect waveguides is tuned to obtain the two matched dispersion relations, where one of the dispersion relations has a maximum point with zero group velocity and large positive GVD; the other has a minimum point with zero group velocity and large negative GVD. The waveguides have ultra slow light with the group velocity 0.0012c. Finite-difference time-domain simulation demonstrates that the spreading of the slow light pulse in the first waveguide can be recovered by the dispersion compensation of the second waveguide with positive GVD.


PIERS Online ◽  
2010 ◽  
Vol 6 (3) ◽  
pp. 273-278 ◽  
Author(s):  
David J. Moss ◽  
B. Corcoran ◽  
C. Monat ◽  
Christian Grillet ◽  
T. P. White ◽  
...  

Nanophotonics ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 2377-2385 ◽  
Author(s):  
Zhao Cheng ◽  
Xiaolong Zhu ◽  
Michael Galili ◽  
Lars Hagedorn Frandsen ◽  
Hao Hu ◽  
...  

AbstractGraphene has been widely used in silicon-based optical modulators for its ultra-broadband light absorption and ultrafast optoelectronic response. By incorporating graphene and slow-light silicon photonic crystal waveguide (PhCW), here we propose and experimentally demonstrate a unique double-layer graphene electro-absorption modulator in telecommunication applications. The modulator exhibits a modulation depth of 0.5 dB/μm with a bandwidth of 13.6 GHz, while graphene coverage length is only 1.2 μm in simulations. We also fabricated the graphene modulator on silicon platform, and the device achieved a modulation bandwidth at 12 GHz. The proposed graphene-PhCW modulator may have potentials in the applications of on-chip interconnections.


Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali Rostamian ◽  
Ehsan Madadi-Kandjani ◽  
Hamed Dalir ◽  
Volker J. Sorger ◽  
Ray T. Chen

Abstract Thanks to the unique molecular fingerprints in the mid-infrared spectral region, absorption spectroscopy in this regime has attracted widespread attention in recent years. Contrary to commercially available infrared spectrometers, which are limited by being bulky and cost-intensive, laboratory-on-chip infrared spectrometers can offer sensor advancements including raw sensing performance in addition to use such as enhanced portability. Several platforms have been proposed in the past for on-chip ethanol detection. However, selective sensing with high sensitivity at room temperature has remained a challenge. Here, we experimentally demonstrate an on-chip ethyl alcohol sensor based on a holey photonic crystal waveguide on silicon on insulator-based photonics sensing platform offering an enhanced photoabsorption thus improving sensitivity. This is achieved by designing and engineering an optical slow-light mode with a high group-index of n g  = 73 and a strong localization of modal power in analyte, enabled by the photonic crystal waveguide structure. This approach includes a codesign paradigm that uniquely features an increased effective path length traversed by the guided wave through the to-be-sensed gas analyte. This PIC-based lab-on-chip sensor is exemplary, spectrally designed to operate at the center wavelength of 3.4 μm to match the peak absorbance for ethanol. However, the slow-light enhancement concept is universal offering to cover a wide design-window and spectral ranges towards sensing a plurality of gas species. Using the holey photonic crystal waveguide, we demonstrate the capability of achieving parts per billion levels of gas detection precision. High sensitivity combined with tailorable spectral range along with a compact form-factor enables a new class of portable photonic sensor platforms when combined with integrated with quantum cascade laser and detectors.


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