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Message ID: 2424     Entry time: Mon Sep 23 23:48:12 2019
Author: Koji 
Type: Update 
Category: 2micronLasers 
Subject: 2um sensor cards / focusing optics 

Fiber Collimator (Thorlabs F028APC-2000+AD11F+LMR1) and MIR sensor cards (Thorlabs VRC6S Qty2) were delivered.

The sensor card is liquid crystal and seems temperature sensitive. It's slow and diffused. But at least we can now see 2um beams in a certain condition.

The fiber collimator seems working fine, but this gave me another issue. Now because the beam is small (w<500um) everywhere, I can't focus it very well. To make a focused beam, one needs a large beam, of course. Previously, the beam was not well focused. Therefore the final focused beam with f=150mm was sufficiently small like w=50um.

It looks like some kind of  telescope is necessary.

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