How Light Travels Through Plasmonic-Photonic Crystals

A group of researchers led by Myakzyum Salakhov has been working on the problem of optical states in plasmonic-photonic crystals (PPCs). Artyom Koryukin comments that the research was dedicated to modelling light trans­mission throughout photonic crystals with a continuous gold layer on their surface. Photonic crystals don’t pass a certain wave­length of light cause of the photonic bandgap. PPCs, on the contrary, allow the passing of light of a certain wave­length in this photonic bandgap. The problem of three-dimen­sional opal-like PPCs (OLPPCs), however, is that they don’t admit light of certain wavelengths.

Scheme of a plasmonic-photonic crystal (PPC) with equal effective refractive index and structure period. (Source: Kazan Fed. U.)

Now, conditions are defined for the passing of a beam of light with the wave­length of the photonic bandgap and certain polari­zation through an OLPPC. To achieve this goal, different versions of PPCs were modelled. The main conditions to pass such a beam are both the conti­nuity of the gold layer with thickness of about forty nanometers and the use of light with polari­zation. Trans­mittance of light across a PPC is accom­panied by excitations of the optical Tamm states.

One- dimensional PPC has a light trans­mission pass bands inside the photonic bandgap in both polarizations. Three-dimen­sional PPCs do not have light transmission pass bands inside the photonic bandgap because of a non-continuous gold layer – shaped like separate nano-caps or nano-crescents on the surface of a PPC. So the used OLPPCs have this unique feature – they have a light trans­mission pass band inside the photonic bandgap with certain polari­zation due to the excitation of the hybrid mode of the optical states.

OLPPCs with the hybrid mode of the optical states can be used in high-polari­zation-sensitive sensors. “We assume that the hybrid mode can be useful for improving the control of light in PPCs. New types of resonators based on OLPPCs can be used for the strong inter­action of light and matter,” said Koryukin. The group is planning to create a theo­retical description of the model of such processes. Addi­tionally, they want to find effective appli­cations for OLPPCs, such as strong light-matter inter­actions with a single photon source. (Source: Kazan Fed. U.)

Reference: A. V. Koryukin et al.: Hybrid Mode of Optical States in Opal-like Plasmonic-Photonic Crystals, Plasmonics 14, 961 (2019); DOI: 10.1007/s11468-018-0880-6

Link: Institute of Physics, Kazan Federal University, Kazan, Russia

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