Buried Nd: gadolinium garnet waveguide lasers grown by pulsed laser deposition
Buried Nd: gadolinium garnet waveguide lasers grown by pulsed laser deposition
Pulsed laser deposition (PLD) has often been avoided as a preferred fabrication method due to the large number of particulates generated on the waveguides during growth. We have grown uncapped and buried Nd:GGG waveguide lasers, as before[1], to study the effect of particulates on the lasing power threshold. A comparison between the lasing power threshold of the waveguide and the particulate density is shown in fig.1. It can be seen that the effect of the particulates has a far more dramatic effect on those guides with increased confinement. An increase in particulate density from 3.5 x 104 to 9.7 x 105 particulates led to an increase in absorbed power threshold from 2.5mW to 167mW. A 4µm thick guide with a particulate density of 3.2 x 106 particulates cm-2, however, lased easily at 19mW where a 2µm thick waveguide would be unable to lase at the pump powers available. Even an increase up to 1 x 107 particulates cm-2 (a very poor quality film) would still allow lasing at around 60mW. The 8µm thick waveguide showed good waveguide performance regardless of particulate density, lasing at 2.2mW and 12.2mW with particulate densities of 5.5 x 104 cm-2 and 6.6 x 106 respectively, a change in particulate density of over 2 orders of magnitude. The particulate density of the Capped layer is higher than that of the other 4µm unclad waveguides at 1.5 x 107 cm-2. A film with such a high particulate density has been made in a 4µm unclad structure but was unable to lase at the incident laser powers available (~700mW @ 808nm). The buried laser had a lasing threshold of 14.8mW of absorbed power. For comparison lasing action in an uncapped layer with a particulate density 4 times lower was observed at 19mW absorbed power. Two new implementations to the traditional PLD apparatus of scanned CO2 laser heating and off-centre multiple rotational targets have been used in the course of fabrication to increase the homogeneity of the films. These techniques will be discussed further.
Barrington, S.J.
bf10bec5-2c40-4470-a0ef-5bcc69282d1a
Eason, R.W.
e38684c3-d18c-41b9-a4aa-def67283b020
2001
Barrington, S.J.
bf10bec5-2c40-4470-a0ef-5bcc69282d1a
Eason, R.W.
e38684c3-d18c-41b9-a4aa-def67283b020
Barrington, S.J. and Eason, R.W.
(2001)
Buried Nd: gadolinium garnet waveguide lasers grown by pulsed laser deposition.
CLEO/Europe-EQEC2001: Conference on Lasers and Electro-Optics. European Quantum Electronics Conference, Munich, Germany.
17 - 21 Jun 2001.
1 pp
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
Pulsed laser deposition (PLD) has often been avoided as a preferred fabrication method due to the large number of particulates generated on the waveguides during growth. We have grown uncapped and buried Nd:GGG waveguide lasers, as before[1], to study the effect of particulates on the lasing power threshold. A comparison between the lasing power threshold of the waveguide and the particulate density is shown in fig.1. It can be seen that the effect of the particulates has a far more dramatic effect on those guides with increased confinement. An increase in particulate density from 3.5 x 104 to 9.7 x 105 particulates led to an increase in absorbed power threshold from 2.5mW to 167mW. A 4µm thick guide with a particulate density of 3.2 x 106 particulates cm-2, however, lased easily at 19mW where a 2µm thick waveguide would be unable to lase at the pump powers available. Even an increase up to 1 x 107 particulates cm-2 (a very poor quality film) would still allow lasing at around 60mW. The 8µm thick waveguide showed good waveguide performance regardless of particulate density, lasing at 2.2mW and 12.2mW with particulate densities of 5.5 x 104 cm-2 and 6.6 x 106 respectively, a change in particulate density of over 2 orders of magnitude. The particulate density of the Capped layer is higher than that of the other 4µm unclad waveguides at 1.5 x 107 cm-2. A film with such a high particulate density has been made in a 4µm unclad structure but was unable to lase at the incident laser powers available (~700mW @ 808nm). The buried laser had a lasing threshold of 14.8mW of absorbed power. For comparison lasing action in an uncapped layer with a particulate density 4 times lower was observed at 19mW absorbed power. Two new implementations to the traditional PLD apparatus of scanned CO2 laser heating and off-centre multiple rotational targets have been used in the course of fabrication to increase the homogeneity of the films. These techniques will be discussed further.
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Published date: 2001
Venue - Dates:
CLEO/Europe-EQEC2001: Conference on Lasers and Electro-Optics. European Quantum Electronics Conference, Munich, Germany, 2001-06-17 - 2001-06-21
Organisations:
Optoelectronics Research Centre
Identifiers
Local EPrints ID: 17163
URI: http://eprints.soton.ac.uk/id/eprint/17163
PURE UUID: 25cb0744-edae-4122-ab32-f9dca68f178e
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Date deposited: 16 Sep 2005
Last modified: 12 Dec 2021 02:38
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Author:
S.J. Barrington
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