Photonic Crystals and Metamaterials: Physics and Applications

TOPIC CLASSIFICATION

Subject: Science & Technology - Physics - Photonics and Advanced Materials
Sub-topic: Photonic Crystals - Photonic Band Gap, Periodic Dielectric Structures, 1D/2D/3D Photonic Crystals, Applications (Optical Fibres, Lasers, LEDs, Solar Cells); Metamaterials - Negative Refractive Index, Left-Handed Materials, Cloaking, Superlens, Perfect Lens, Electromagnetic Invisibility, Metasurfaces; Fabrication Techniques; India's Research - DRDO Metamaterials, IIT Photonics, Raman Research Institute
Mains GS Paper-III: Science & Technology - developments in physics, photonics, and advanced materials; their applications in defence, communication, and energy.

---

EXAMINER REASONING

Photonic crystals and metamaterials represent breakthroughs in controlling light beyond what natural materials allow. Prelims tests: photonic crystal definition (periodic dielectric structures - optical analog of semiconductors), photonic band gap, 1D/2D/3D photonic crystals (Bragg mirrors, photonic crystal fibres), metamaterials (sub-wavelength structures), negative refractive index, superlens (beyond diffraction limit), cloaking, DNG (double negative) materials - negative ε and μ simultaneously. Mains demands: (a) photonic crystals - periodic modulation of refractive index - creates photonic band gap (range of wavelengths that cannot propagate) - similar to electronic band gap in semiconductors, (b) applications of photonic crystals - photonic crystal fibres (endlessly single-mode - high power transmission), photonic crystal lasers (low threshold - VCSELs), LEDs (enhanced extraction efficiency),...