Frequency doubler / tripler

• Remove first dichroic beamsplitter for switching between doubling and tripling [left # 6, 2 screws]
• Red filter on output blocks fundamental (or doubled ?)
• Rotate axis of second crystal is test for really tripling the light
• Time overlap fundamental and doubled is very critical
• To focus the light in the second crystal, use the horizontal knob
• Overlap fundamental and 2 nd harmonic use second mirror 14
• Fundamental and doubled are co-linear
• To make better collinear : beamwalking of 2x mirror 14
• Top : tripled, bottom doubled.
• Instead of red filter, use UG11 with tape on the top hole, to block the doubled light
• SHG crystal is now 3 mm, instead of original 1.5 mm. Fast times are not very important.

Both doubler and tripler tuning knob : clockwise to higher wavelength.

2nd crystal (BBO) is now 2 mm.

Verdi : 4.5 W
810 nm → 405 nm, 2 MHz : 0.55 mW

Verdi : 5 W
885 nm → 295 nm, 2 MHz : 28 micro watt

13-7-2015
Verdi 5W, humidity : 33%
895 nm, monitor 129 (modelocked) : 26 microwatt doubled
907 nm, monitor 122 (modelocked) : 3.6 microwatt tripled
909 nm, monitor 118 (modelocked) : 2.6 microwatt tripled
911 nm, monitor 108 (modelocked) : 0.8 microwatt tripled

21-9-2015
Verdi 5W, humidity 34%, 911 nm, monitor 109 (modelocked) : 7 microwatt tripled.
Ben helped :
- FdH : also used the fine tuning of the Mira : this helped a bit.
- In pulse picker : adjusted height helped a bit.
- First #14 mirror tweaked = overlap Fund. & SHG : this helped.
- Better time overlap : it looked that the time overlap got stuck. Maybe the delay stage is dirty & stuck. Try push.
- Whilelooking at the THG power, change prism of mira a bit : this can make the pulse shorter.

10-11-2015
Verdi 5W, humidity 34%, 811 nm, monitor
Doubled output 0.36 mW (2MHz) Should be more ?