PHOTONIC CRYSTALS AND DEVICES HAVING TUNABILITY AND SWITCHABILITY

• US 20040027646A1
• Filed: 08/09/2002
• Published: 02/12/2004
• Est. Priority Date: 08/09/2002
• Status: Active Grant

• Current Assignee: Energy Conversion Devices
• Original Assignee: Energy Conversion Devices
• Inventors: Miller, Robert O., Tsu, David
• Granted Patent: US 6,859,304 B2
• Time in Patent Office: Days
• US Class Current: 359/322
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 6/12007 forming wavelength selective elements, e.g. multiplexer, demultiplexer
• CPC Class Codes: G02B 6/1225 comprising photonic band-gap structures or photonic lattices
• CPC Class Codes: G02F 1/0054 Structure, phase transitions, NMR, ESR, Moessbauer spectra
• CPC Class Codes: G02F 1/011 in optical waveguides, not otherwise provided for in this subclass
• CPC Class Codes: G02F 1/0147 based on thermo-optic effects G02F1/132 takes precedence
• CPC Class Codes: G02F 2202/32 Photonic crystals
• CPC Class Codes: H01P 1/2005 Electromagnetic photonic bandgaps [EPB], or photonic bandgaps [PBG]

Abstract

A photonic crystal having reversibly tunable photonic properties. The photonic crystal includes a phase change material having a plurality of structural states that vary with respect to fractional crystallinity. Optical constants including refractive index, extinction coefficient and permittivity vary as the fractional crystallinity of the phase change material is varied thereby providing tunability of photonic crystal properties. Variations among the structural states of the phase change material are reversibly effected through the addition of energy in forms including optical or electrical energy. The photonic crystals may include defects that provide photonic states within the photonic band gap. The position of these states is tunable through the control of the fractional crystallinity of the phase change material included in the photonic crystal. Electromagnetic radiation resonators including photonic crystals having photonic states in the photonic band gap are further provided. These resonators may be used for frequency selective filtering or routing of electromagnetic radiation and permit tunable variation in the frequency and decay rates of resonant modes through control of the structural state of the phase change material. These resonators are further coupled to waveguides to provide tunable channel drop filters and narrowband reflectors.

Claims

6-1. The photonic crystal of claim 1, wherein the refractive index of said amorphous state and said crystalline state differ by at least 50% at one or more frequencies within the photonic band gap of said photonic crystal.