Ultra-thin optical coatings and devices and methods of using ultra-thin optical coatings

US9952096B2 · kind B2 · utility

Assignee

• President and Fellows of Harvard College · US

Inventors

• Mikhail Kats · Rockaway, US
• Romain Blanchard · Cambridge, US
• Patrice Genevet · Cambridge, US
• Federico Capasso · Westfield, US

Key dates

• Filing date: Jun 3, 2013
• Grant date: Apr 24, 2018
• Expiry date: Dec 15, 2034

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/50
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A spectral encoder includes a thin layer of lossy dielectric material whose thickness varies transversely from 0 to a thickness of about λ/4n (e.g., <100 nm), where λ is the wavelength of incident radiation and n is the dielectric material's refractive index. The dielectric layer reflects (and/or transmits) light at a wavelength that depends on the layer's thickness. Because the dielectric layer's thickness varies, different parts of the dielectric layer may reflect (transmit) light at different wavelengths. For instance, shining white light on a dielectric layer with a linearly varying thickness may produce a rainbow-like reflected (and/or transmitted) beam. Thus, the spectral encoder maps different wavelengths to different points in space. This mapping can be characterized by a transfer matrix which can be used to determine the spectrum of radiation incident on the spectral encoder from the spatial intensity distribution of the radiation reflected (and/or transmitted) by the spectral encoder.