7-11 July 2014
Africa/Johannesburg timezone
<a href="http://events.saip.org.za/internalPage.py?pageId=16&confId=34"><font color=#0000ff>SAIP2014 Proceedings published on 17 April 2015</font></a>

Thermally induced lensing determination from the coefficient of defocus aberration

9 Jul 2014, 17:10
1h 50m
D Ring ground level

D Ring ground level

Board: C.270
Poster Presentation Track C - Photonics Poster2


Mr July Bell (UKZN)

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Abstract content <br> &nbsp; (Max 300 words)<br><a href="http://events.saip.org.za/getFile.py/access?resId=0&materialId=0&confId=34" target="_blank">Formatting &<br>Special chars</a>

The effects of lensing due to a temperature gradient in a laser crystal as a result of an end-pumped configuration in a solid-state laser resonator were investigated. It is well known that as the result of thermally induced lensing, the effective length of a laser cavity is altered, thus altering the properties of the selected mode at the output of the laser. Typically, the radius of curvature of a lens may be described from the coefficient of the defocus aberration, which can be described from the set of orthogonal Zernike polynomials. The defocus coefficient of known lenses (physical and digital) was measured using a Shack-Hartmann wave-front sensor, as a calibration technique. With this we probe a Nd:YAG gain medium with a collimated Gaussian beam operating at 633 nm and the coefficient of the defocus aberration under active pumping at a variety of pump powers was measured. The position of measurement inside the crystal is varied relative to the end-pumped surface and the resulting focal lengths are compared to typical thermal lens measured data in active end-pumped solid-state lasers.

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Main supervisor (name and email)<br>and his / her institution

Prof. A. Forbes

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Primary author

Mr July Bell (UKZN)


Prof. Andrew Forbes (CSIR) Mr Darryl Naidoo (Council for Scientific and Industrial Research)

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