Page 9 - Two-chord Interferometry using 3.39 µm He-Ne Laser on a Flux-Coil-Generated FRC
P. 9
9 HTPD2010, Wildwood, NJ, 5/17/2010
Presenter: Hiroshi Gota
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Optical Layout of the Interferometer System
He-Ne CW Lasers:
~2 mW minimum output power of λ~3.39 μm laser (Research Electro-Optics, model LHIP-0201-339) for the interferometry, and <1 mW output power of λ~632.8 nm self-contained laser (CVI Melles Griot, model 05LLR811) for the alignment. The IR laser beam has ~2 mm diameter and ~2.1 mrad divergence.
Acousto-Optic Modulator:
A 40 MHz AOM (IntraAction Corp., model AGM-403FB3) is used to split the IR laser beam into a probing and a reference beams, and both beams are split in half by the ZnSe beamsplitter for the two-chordal measurements.
Photodetectors:
An IR detector (Vigo system, model PVI-5) is a photovoltaic type with a responsivity of ~4.2 A/W at ~3.39 μm, and the bias voltages of −0.5 V are applied through the bias-tees onto each detector to obtain a faster response time.
