Ultrafast revealing of invisible patterns encrypted in colloidal photonic crystals

Kuo Zhong; Kai Song; Koen Clays

doi:10.1117/12.2320945

7 September 2018 Ultrafast revealing of invisible patterns encrypted in colloidal photonic crystals

Kuo Zhong, Kai Song, Koen Clays

Proceedings Volume 10724, Physical Chemistry of Semiconductor Materials and Interfaces XVII; 107241D (2018) https://doi.org/10.1117/12.2320945
Event: SPIE Nanoscience + Engineering, 2018, San Diego, California, United States

Abstract

We describe the necessary steps towards the realization of ultrafast revealing of invisible patterns encrypted in colloidal photonic crystals. These include the development of hollow air-core – dense-silica-shell core-shell monodisperse and spherical nanoparticles; introducing of a pattern of hydrophilic regions in a hydrophobic surrounding; and the combination of these two approaches by selective oxygen plasma etching of hollow core-shell nanospheres. The pattern imprinted by the difference in only surface property remains invisible in normal conditions of static environmental humidity. The hydrophilic regions in the patterns are reversible and immediately unveiled by dynamic humid flow. The specific properties of a human breath in terms of relative humidity and vapor flow are ideal for optimal revealing in terms of the spectral shift of the photonic bandgap of the colloidal crystal. The revealing of the pattern is determined by the surface tension of the vapor, while the color of the imprinted pattern is independently determined by its refractive index.

Citation Download Citation

Kuo Zhong, Kai Song, and Koen Clays "Ultrafast revealing of invisible patterns encrypted in colloidal photonic crystals", Proc. SPIE 10724, Physical Chemistry of Semiconductor Materials and Interfaces XVII, 107241D (7 September 2018); https://doi.org/10.1117/12.2320945

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available