Expand this Topic clickable element to expand a topic
Skip to content
Optica Publishing Group
  • CLEO/Europe and EQEC 2011 Conference Digest
  • OSA Technical Digest (CD) (Optica Publishing Group, 2011),
  • paper CB8_2

Flexible distributed feedback colloidal quantum dot laser patterned by a submicron grating structure

Not Accessible

Your library or personal account may give you access

Abstract

Flexible optoelectronics is rapidly finding a niche for applications in areas such as flexible displays, sensors, solar cells and electronic paper, where low-cost, robustness, light weight and ease of fabrication are important advantages compared to their rigid-substrate counterparts [1]. We have been focusing on the study of flexible lasers using solution-based gain materials [2,3] and have developed a technique for replicating grating structures onto flexible substrates to form the basis of distributed-feedback (DFB) lasers. Colloidal quantum dots (CQDs) are attractive solution-based gain materials and are promising for laser devices due to their spectral tunability and temperature stability [4]. In this work, we report what we believe to be the first flexible DFB CQD laser. An exposed standard commercial blank digital versatile disk (DVD) was used as the mask to fabricate a submicron scale grating structure, providing a simple and low-cost approach. A UV transparent polymerisable host matrix, 1,4-cyclohexanedimethanol divinyl ether (CHDV), was then photo-cured to replicate the DVD grating structure and peeled off from the mask, resulting in a flexible grating [Fig. 1(a)]. The thickness of the grating substrate can be controlled in the range of 50 to 300 μm. The 740-nm period structure acts as a higher order (4th) diffraction grating for the CQD red emission and its 100-nm modulation depth yields sufficient feedback for laser oscillation [3]. Solution-based CdSe/ZnS core-shell CQDs were drop-coated onto it to form the gain layer of which thickness can be controlled via the coating process. A frequency-tripled Q-switched Nd:YAG laser (5-ns pulse, 10-Hz repetition rate and 355-nm excitation wavelength) was then used to photo-pump the CQD sample [Fig. 1(b)]. The emission evolution was investigated [Fig. 1(c)] and a 4 mJ/cm2 lasing threshold was found, comparing favourably to other reports of CQD lasers [4]. The polarisation of the laser emission revealed that the DFB CQD laser favours a linearly polarized (TE) emission. During the experiment, the laser performance, operating above lasing threshold at room temperature and ambient atmosphere, was stable over more than 10,000 pump pulses.

© 2011 Optical Society of America

PDF Article
Select as filters


Select Topics Cancel
© Copyright 2024 | Optica Publishing Group. All Rights Reserved