Dr. Tilmann E. Ruhl Profile

Dr. Tilmann E. Ruhl

at Technische Univ Darmstadt

SPIE Involvement:

Author

Publications (2)

This will count as one of your downloads.

You will have access to both the presentation and article (if available).

DOWNLOAD NOW

This content is available for download via your institution's subscription. To access this item, please sign in to your personal account.

Email or Username Forgot your username?

Password Forgot your password?

Show

Keep me signed in

No SPIE account? Create an account

Proceedings Article | 18 April 2006 Paper

Photonic crystals from inorganic-polymeric hybrid-particles

T. Ruhl, P. Spahn, C. Jamois, C. Hermann, O. Hess

Proceedings Volume 6182, 61820J (2006) https://doi.org/10.1117/12.662898

KEYWORDS: Optical spheres, Silica, Particles, Photonic crystals, Switching, Crystals, Tin, Polymers, Refractive index, Composites

Read Abstract +

Photonic crystals exhibit exciting opportunities for controlling light. This can be utilized in optical waveguides, telecommunication devices, chemical and biological sensing and solar cells. However, functional devices require tuneable photonic crystals and ultimately structures that allow switching. Therefore inorganic-polymeric hybrid particles were developed, which offer new opportunities in the design of nanostructured materials since each component can be removed selectively. The presentation describes the synthesis of silica-polymer core-shell particles, absolutely uniform in size and in architecture. They were used as building blocks for colloidal crystals which served as templates for titania or tin disulfide inverse opals. Due to the inorganic-polymeric core-shell structure of the spheres, removing the polymeric shells by calcination yields the structure of Double Inverse Opal Photonic Crystals (DIOPC): The ordered, 3D array of air spheres in a high refractive index backbone is a host for movable silica spheres which behave as weakly scattering objects. The optical properties were determined by reflectivity measurements. Infiltration with liquids masks the silica-spheres optically, therefore introducing a transition of a diffusive scattering material to a selective reflection of specific wavelengths as known from ordinary inverse opals. This experiment simulates an order-disorder transition, induced by a collective shift of the random distributed silica-spheres into one specific position in the pores. The potential of switching a complete band-gap by a collective shift of the spheres to specific positions in the pores of the DIOPC is demonstrated by computational analysis.

Proceedings Article | 15 September 2004 Paper

Large-area photonic crystals

Tilmann Ruhl, Peter Spahn, Gotz Hellmann, Holger Winkler

Proceedings Volume 5450, (2004) https://doi.org/10.1117/12.546469

KEYWORDS: Particles, Polymers, Silica, Photonic crystals, Crystals, Optical spheres, Reflection, Refractive index, Dispersion, Etching

Read Abstract +

Materials with a periodically modulated refractive index, with periods on the scale of light wavelengths, are currently attracting much attention because of their unique optical properties which are caused by Bragg scattering of the visible light. In nature, 3d structures of this kind are found in the form of opals in which monodisperse silica spheres with submicron diameters form a face-centered-cubic (fcc) lattice. Artificial opals, with the same colloidal-crystalline fcc structure, have meanwhile been prepared by crystallizing spherical colloidal particles via sedimentation or drying of dispersions. In this report, colloidal crystalline films are introduced that were produced by a novel technique based on shear flow in the melts of specially designed submicroscopic silica-polymer core-shell hybrid spheres: when the melt of these spheres flows between the plates of a press, the spheres crystallize along the plates, layer by layer, and the silica cores assume the hexagonal order corresponding to the (111) plane of the fcc lattice. This process is fast and yields large-area films, thin or thick. To enhance the refractive index contrast in these films, the colloidal crystalline structure was inverted by etching out the silica cores with hydrofluoric acid. This type of an inverse opal, in which the fcc lattice is formed by mesopores, is referred to as a polymer-air photonic crystal.

My Library

You currently do not have any folders to save your paper to! Create a new folder below.

Folder Name

Folder Description

View contact details

UPDATE YOUR PROFILE

Is this your profile? Update it now.

Sign into your SPIE.org account

Don’t have a profile and want one?

Create an account on SPIE.org

Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks. You are receiving this notice because your organization may not have SPIE eBooks access.*

*Shibboleth/Open Athens users─please sign in to access your institution's subscriptions.

To obtain this item, you may purchase the complete book in print or electronic format on SPIE.org.

ORGANIZATIONAL
Sign in with credentials provided by your organization.

Organizational Username

Organizational Password

Show/Hide Password

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

Members:

Non-members: ADD TO CART

Keywords/Phrases

Search In:

Publication Years