- Aligned the imaging unit. Using a blade at about 1cm from the crossing point. I moved the lens on the imaging unit until I saw a sharp image of the blade at the detector position.

- Using the surface reference sample I aligned the pump with the probe to maximize the signal. Then I maximized the signal finely adjusting  the position of the whole imaging unit.

- I noticed that there was some noise (around 300uV in the AC signal) with a constant phase. It came from the chopper vibration. So I put some sound absorbing panels and the noise reduced to about 50uV.

- I made a scan of the bulk reference sample with a pump power of 32mW

- I made a scan of the tama-size sapphire and I got the same absorption as before changing the pump size. 

- Compared the scans of the bulk reference sample with small pump and large pump. They give the same value (unexpected) but they have a different shape. To be understood.