Characterization of high power laser diode as a solid state pumping source

Laser diode is popular to be used as an optical pumping source, taking an advantage because it is small in size and light in weight. On the other hand, the laser diode creates a lot of heat dissipation because it was injected by a current. Due to the cuteness of active medium, it will generate a lar...

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Main Author:	Md. Jani, Mohd. Fairuz
Format:	Thesis
Language:	English
Published:	2008
Subjects:	TA Engineering (General) Civil engineering (General)
Online Access:	http://eprints.utm.my/id/eprint/17979/1/MohdFairuzMdJaniMFS2008.pdf
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spelling	my-utm-ep.179792018-06-29T21:51:17Z Characterization of high power laser diode as a solid state pumping source 2008-12 Md. Jani, Mohd. Fairuz TA Engineering (General). Civil engineering (General) Laser diode is popular to be used as an optical pumping source, taking an advantage because it is small in size and light in weight. On the other hand, the laser diode creates a lot of heat dissipation because it was injected by a current. Due to the cuteness of active medium, it will generate a large beam divergence. In attempt to demonstrate the issue and overcome these problems, two laser diodes were characterized and an investigation is carried out to stabilize the output. The first laser diode bar was purposely employed to highlight the issue of beam divergence. The second laser diode is highly collimated and capable to be focused. However, both lasers are not stable, meaning no cooling is provided. Two collimators model FLA40B and FLA15 were used to reduce the beam divergence of laser diodes. The stability of laser diode is identified by operating the laser in free running mode. Knowing that the output turn out to be very small, the result indicates that the laser required stabilizer. Fan extractor and heat sink were introduced in the system. Realizing that the output is still not stable, a Thermoelectric Cooler (TEC) was designed and constructed. After stabilizing the lasers system, they were utilized to pump orthovanadate Nd:YVO4 crystal disk. The fluorescence beams were detected via spectrum analyzer. The pumping by using collimated high power laser diode was further enhanced by focusing the beam into an active medium and filtering the emission radiation using IR filter. The result obtained shows that, the laser diode produce output power of 1.8 W without cooling system with differential responsivity of 0.21 W/A and an efficiency of 8%. With TEC provided the laser power increased up to 4.6 W with power conversion of 12%. The output power of collimated beam achieved up to 8.6 W with differential responsivity of 0.54 W/A and an efficiency of 27%. Both laser diodes produced fundamental wavelength center at 808 nm. This is a suitable absorption band for orthovanadate crystal. However, the spectrum gain of the laser diodes is kept on broadening at higher pumping current. Changes in refractive index and the increase in active zone were the cause to the spectrum gain’s broadening. The emission spectrum comprised of 878 nm, 917 nm with majority line of 1064 nm. It is also noticed that by focusing the high power laser diode and filtering the output, the emission radiation becomes more pronounce and significant. 2008-12 Thesis http://eprints.utm.my/id/eprint/17979/ http://eprints.utm.my/id/eprint/17979/1/MohdFairuzMdJaniMFS2008.pdf application/pdf en public masters Universiti Teknologi Malaysia, Faculty of Science Faculty of Science
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	TA Engineering (General) Civil engineering (General)
spellingShingle	TA Engineering (General) Civil engineering (General) Md. Jani, Mohd. Fairuz Characterization of high power laser diode as a solid state pumping source
description	Laser diode is popular to be used as an optical pumping source, taking an advantage because it is small in size and light in weight. On the other hand, the laser diode creates a lot of heat dissipation because it was injected by a current. Due to the cuteness of active medium, it will generate a large beam divergence. In attempt to demonstrate the issue and overcome these problems, two laser diodes were characterized and an investigation is carried out to stabilize the output. The first laser diode bar was purposely employed to highlight the issue of beam divergence. The second laser diode is highly collimated and capable to be focused. However, both lasers are not stable, meaning no cooling is provided. Two collimators model FLA40B and FLA15 were used to reduce the beam divergence of laser diodes. The stability of laser diode is identified by operating the laser in free running mode. Knowing that the output turn out to be very small, the result indicates that the laser required stabilizer. Fan extractor and heat sink were introduced in the system. Realizing that the output is still not stable, a Thermoelectric Cooler (TEC) was designed and constructed. After stabilizing the lasers system, they were utilized to pump orthovanadate Nd:YVO4 crystal disk. The fluorescence beams were detected via spectrum analyzer. The pumping by using collimated high power laser diode was further enhanced by focusing the beam into an active medium and filtering the emission radiation using IR filter. The result obtained shows that, the laser diode produce output power of 1.8 W without cooling system with differential responsivity of 0.21 W/A and an efficiency of 8%. With TEC provided the laser power increased up to 4.6 W with power conversion of 12%. The output power of collimated beam achieved up to 8.6 W with differential responsivity of 0.54 W/A and an efficiency of 27%. Both laser diodes produced fundamental wavelength center at 808 nm. This is a suitable absorption band for orthovanadate crystal. However, the spectrum gain of the laser diodes is kept on broadening at higher pumping current. Changes in refractive index and the increase in active zone were the cause to the spectrum gain’s broadening. The emission spectrum comprised of 878 nm, 917 nm with majority line of 1064 nm. It is also noticed that by focusing the high power laser diode and filtering the output, the emission radiation becomes more pronounce and significant.
format	Thesis
qualification_level	Master's degree
author	Md. Jani, Mohd. Fairuz
author_facet	Md. Jani, Mohd. Fairuz
author_sort	Md. Jani, Mohd. Fairuz
title	Characterization of high power laser diode as a solid state pumping source
title_short	Characterization of high power laser diode as a solid state pumping source
title_full	Characterization of high power laser diode as a solid state pumping source
title_fullStr	Characterization of high power laser diode as a solid state pumping source
title_full_unstemmed	Characterization of high power laser diode as a solid state pumping source
title_sort	characterization of high power laser diode as a solid state pumping source
granting_institution	Universiti Teknologi Malaysia, Faculty of Science
granting_department	Faculty of Science
publishDate	2008
url	http://eprints.utm.my/id/eprint/17979/1/MohdFairuzMdJaniMFS2008.pdf
_version_	1747815163414708224

Characterization of high power laser diode as a solid state pumping source

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