Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group
Journal Home About Issues in Progress Current Issue All Issues Feature Issues

Replicated slanted gratings with a high refractive index material for in and outcoupling of light

Tapani Levola and Pasi Laakkonen

Open Access Open Access

Abstract

Diffractive slanted gratings are manufactured onto plastic light guides using a high refractive index material and UV replication technology. We show that the manufacturing of such components is possible in large quantities. The applications of the slanted gratings are a high efficiency light in- and outcoupling with plastic light guides. We also show that it is possible to control which outcoupling diffraction order, reflective or transmissive, is dominating and hence to maximize the light power to one direction.

©2007 Optical Society of America

Full Article  |  PDF Article
More Like This
A double-sided grating coupler for thin light guides

Samuli Siitonen, Pasi Laakkonen, Jani Tervo, and Markku Kuittinen
Opt. Express 15(5) 2008-2018 (2007)

Optimization of nonbinary slanted surface-relief gratings as high-efficiency broadband couplers for light guides

Benfeng Bai, Janne Laukkanen, Markku Kuittinen, and Samuli Siitonen
Appl. Opt. 49(28) 5454-5464 (2010)

Design and fabrication of blazed gratings for a waveguide-type head mounted display

Marie-Aline Mattelin, Ana Radosavljevic, Jeroen Missinne, Dieter Cuypers, and Geert Van Steenberge
Opt. Express 28(8) 11175-11190 (2020)

View More...

Cited By

Optica participates in Crossref's Cited-By Linking service. Citing articles from Optica Publishing Group journals and other participating publishers are listed here.

Alert me when this article is cited.


Figures (7)
Fig. 1.
Fig. 1. Incoupling (ηT1 ) and back-coupling (2×ηT1 ) of the light in a wide grating area with a binary incoupling grating.

Download Full Size | PDF

Fig. 2.
Fig. 2. Definitions of the parameters of slanted binary grating. The width c of the groove is measured at the half height and the ratio c/d is called the filling ratio. The grating period is d and the grating vertical depth is h. The slanted angle is defined as φ=(φ1+φ2)/2. Generally the angle φ1 must be bigger than the angle φ2 (i.e. causing a positive slope for the grating line).

Download Full Size | PDF

Fig. 3.
Fig. 3. The incoupling of the light in a splitted grating area.

Download Full Size | PDF

Fig. 4.
Fig. 4. Reflection (left) and transmission (right) type outcoupling of slanted gratings.

Download Full Size | PDF

Fig. 5.
Fig. 5. Calculated outcoupling efficiencies of slanted binary gratings as a function of grating vertical depth. The left graphs correspond to the reflection type outcoupling and right hand side the transmissive type outcoupling. The parametrers are λ=532 nm, d=405 nm, φ=35 °, and c/d=55% (episulfide material).

Download Full Size | PDF

Fig. 6.
Fig. 6. Left: A developed photoresist mask on 100 nm thick Cr layer (80 nm Cr+20 nm LRC). The grating period is d=405 nm. Right: An example of the 100 nm thick Cr mask profile after the chlorine dry etching process.

Download Full Size | PDF

Fig. 7.
Fig. 7. Left: A cross section of the manufactured SiO2 mould (grating period is d=405 nm and vertical depth is h=330 nm). Right: UV-replica number 520 showing almost an exact copy of the master mould. The corners are sharp that indicates a good replication degree. The grating lines have a small positive slope (few degrees) caused by the RIBE etching process which is one key factor for the replica separation.

Download Full Size | PDF

Tables (1)

Tables Icon

Table 1. The measured and calculated efficiencies from a replicated slanted grating structure.

View Table
Select as filters
Select Topics Cancel
Top
       
© Copyright 2024 | Optica Publishing Group. All rights reserved, including rights for text and data mining and training of artificial technologies or similar technologies.
Privacy | Terms of Use