Hannover 2013 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 50: Laser applications
Q 50.2: Vortrag
Donnerstag, 21. März 2013, 14:30–14:45, F 142
Thermal lens measurement in commonly used optical components — •Christina Bogan1, Patrick Kwee2, Sabina Huttner3, Stefan Hild3, Benno Willke1, and Karsten Danzmann1 — 1Albert-Einstein-Institut Hannover — 2Massachusetts Institute of Technology — 3University of Glasgow
Thermal lensing is a known effect in optical experiments, which is caused by the absorption in transmissive optics and scales with the laser power. The temperature dependent refractive index in combination with the non-uniform temperature profile in transmitive optics acts on a beam like a lens and is called thermal lens.
We developed a measurement method which allows to determine thermal lensing in commonly used optical components. The beam influenced by the thermal lens is expanded into the eigenmodes of an optical cavity and the modal content in the eigenbasis of the cavity is analyzed. The measured quantity depends neither on beam parameters nor on the position of the optical component under investigation. We demonstrated that this method agrees with a measurement of the relative beam size change performed with a camera including a test with a lens with known focal length.
We measured the thermal lens of different optical components, including an acousto-optic modulator whose thermal lens had a focal lens of more than 7000 m for a laser power of 1 W. These tiny effects are hardly measureable with other methods.