Yes, it is sensitive to the other frequencies, and I am sure I am measuring them. If the situation were reversed, and the first mirror lost more than the second I would understand.
I am investigating the scattering effect, but initial results show nothing significant.
Dear Friends,
Thankyou for your responses, and I shall try and answer your questions:
The power meter is a Gentec Duo, measuring from 100µJ to 100mJ. The beam strength that I am measuring is ~30mJ; the measuring head is a Gentec QE25 series.
The mirrors are at 45º; I have both changed...
I have a problem with which I would appreciate any help that is offered:
I have a 266nm laser (frequency quadrupled 1064nm Nd:YAG), and the energy losses along the route are a little strange. The beam is reflected by two UV mirrors; however, the first mirror loses ~7% of the in-going energy...