Using Pismo pulse picker with 10 fs pulses
Pismo pulse picker is suited for 10 fs pulses of Ti:Sapphire oscillator (700-900nm) with 1- 5 mm beam size.
Question: what is the efficiency of the Pockels cell for 200 nm spectrum
The transmission of Pockels cell is shown below. It's about 3.5 % smaller at the edges of the range then at the central wavelength. The reflectivity of ARC (antireflective coating) of Glan prisms and DKDP will be <0.8 % at the edges of the range (700 and 900 nm) and < 0.4 % at the central wavelength (800 nm) (one face). Total transmission of pulse picker system will be 85-90%.
Also you should take into account that 10fs pulse will be chirped after passing through pulse picker system (2x9mm of Glan prisms material and 16 mm of DKDP) and needs to be compressed to initial duration.
> Question: can be the repetition rate changed continuously from 1-25kHz?
In the case when internal trigger is used the repetition rate is determined in the following way. There is an internal pulsed oscillator with the frequency of 100 MHz. Then we get the needed frequency by dividing the frequency of oscillator by two variables. The first variable X is dicrete. It's values are 16, 256, 4096. The second variable Y is also discrete and changes from 1 to 4096 with step 1.
1kHz = 100 MHz/ 256/ 390
25 kHz = 100 MHz/256/16
or 1.5kHz = 100 MHz/ 16/ 4000
25 kHz = 100 MHz/16/250
Accordingly, we have 374 (X=256) or 3750 (X=16) steps in the range 1-25 kHz. External delay is also possible. I.e. the trigger signal is sent to the picker control unit by an external generator. In this case the rep. rate change step will depend on the external generator parameters. By special request, we can produce a more sophisticated (and more expensive) control unit, using which you'll be able to change the frequency with step 0.2 Hz or less in the range 1 – 25 kHz (but take into account, that the precision of this frequency will be defined by the time delay between neighboring pulses from the femtosecond train (10-12 ns for 100-80MHz)).
Pismo Pulse picker brochure
Del Mar Photonics
4119 Twilight Ridge
San Diego, CA 92130
tel (858) 755-6727
fax (858) 630-2376