OG-B/F. Pulse Pickers with Fixed Gate Open Time
• Compatible with Ti:S and Yb-doped 20-150 MHz ultrafast oscillators
• Suitable for building Ti:S or Yb ultrafast regenerative amplifiers
•Possible operating wavelengths from 200 to 2700 nm
• Rise time down to 700 ps (OG-F model)
• Excellent contrast ratio of >1500:1
• Transmission of complete system >90%
• Multifunctional control unit with adjustable delay generator
• USB control, Windows software+LabView driver
Product overview
Electro-optic pulse pickers with fixed gate duration are widely used in the following applications:
- picking of single laser pulses from a train of pulses;
- reduction of repetition rate of laser pulses;
- building regenerative laser amplifiers: injection of seed pulses into amplifier cavity and ejection of amplified pulses out of amplifier cavity; - pulse slicer, i.e. output amplified pulse contrast improvement via cleaning of “parasitic” pulses.
Optical setup of a pulse picker comprises two crossed polarizers with a Pockels cell placed in between. Pulse selection is performed with the use of the Pockels effect — a short high-voltage electric pulse induces birefringence in the Pockels cell’s optical crystal allowing precise rotation of the polarization plane of a certain laser pulse. Then this pulse may be separated from a train of consecutive pulses by using a polarizer. Since the response time of the Pockels effect is very short, such a unit is suitable for working with dense pulse trains and ultrashort laser pulses.
Electronic control unit of a pulse selector is built using programmable logic components and contains such built-in modules as optical and electronic synchronization, trigger pulse generation, frequency division, multi-channel delay signal generation, high-voltage drivers. The unit allows for multiple usage scenarios given below for integration in various laser setups:
- external or internal trigger;
- synchronization to optical (built-in photodetector) or electric signal;
- two independent delay channel groups, each with its trigger and synchronization signals; spare channels may be used as general purpose delay channels for triggering other experimental equipment (e.g. oscilloscopes, pump lasers, streak-cameras etc.);
-additional control modes with triggering by edge/level of an external signal or via a built-in burst generator allow formation of various output pulse patterns;
- up to 4 synchronized Pockels cells may be driven by a single electronic control unit.
OG-F-D
OG-B-D
OG-B-B
OG-B-R/K
Electrooptic crystal
DKDP
BBO
RTP or KTP
Operational wavelength range (standard models)
510-540 nm / 700-1000 nm / 1000-
1100 nm / 1250 nm
510-540 nm / 700-1000 nm /
1000-1100 nm / 1250 nm
1000-1100 nm / 1500-
1600 nm / 1550+780 nm
Possible custom wavelengths
from 340 to 1280 nm
from 200 to 2200 nm
from 1000 to 2700 nm
Minimum repetition rate of picked pulses
single-shot
Maximum repetition rate of picked pulses (standard models)
1 kHz
3 kHz / 10 kHz / 50 kHz / 100 kHz
3 kHz / 10 kHz / 50 kHz / 100 kHz / 200 kHz / 1 MHz
Clear aperture
6 mm
6 mm (up to 20 mm upon request)
2.5 mm (up to 5 mm upon request)
3.5 mm (up to 10 mm upon request)
HV pulse (gate) shape
bell-shaped
HV pulse (gate) length (at level 10%)
3 ns
8 ns
Rise time
(at level 10-90%)
700 ps
3.5 ns
Fall time
(at level 90-10%)
2 ns
3.5 ns
Contrast(1)
>1500:1
>700:1
>800:1
Pockels cell voltage
up to 10 kV
up to 4 kV
up to 3 kV
Optical scheme
half-wave
(quarter-wave upon request)
half-wave/quarter-wave at λ<600 nm; at λ>600 nm - quarter-wave or half-wave with double crystal cell
half-wave (quarter-wave upon
request)
Trigger
internal/external
Complete system transmis- sion at central wavelength
>85% (PC + two Glan-Taylor prisms, default package)
>90% (PC + a Glan-Taylor and a Rochon prism, upon request)
>98% (Pockels cell only)
Input optical train repetition rate
2 MHz …150 MHz with internal or external trigger with optical or electric sync to input train; 1 Hz…2 MHz only with external trigger signal(2)
Sync source for internal trig- ger mode
optical/electric
Additional control modes
by edge / by level / built-in burst generator with internal or external trigger
Channel delay time
0...10 us (up to 1 ms upon request)(3)
0...1 us (up to 5 us upon request)(3)
Cooling
passive at up to 3 kHz output rate, water-cooled(4) at 10 kHz and higher
(1) - energy ratio of a picked and any non-picked pulse. The given contrast values are valid for adjacent pulses;
(2) - when operating with 1 Hz…2 MHz input pulse train, an external trigger signal must be used. Such a signal must lead the optical pulse by 0.25-3 us, must be rigidly in sync with the pulse to be picked and must have jitter of less than 200 ps;
(3) - maximum channel delay time is defined by maximum repetition rate of picked pulses and cannot exceed the temporal distance between adjacent pulses at this frequency;
(4) - the HV generator unit requires cooling to support operating temperature below 35°C. Water cooling is required when operating at output frequency of 10 kHz and more (water flow 1 L/min, water temp. 20-22°C, tap or building-scale supply may be also be used if permitted). Heating
power to be dissipated does not exceed 80 W even at the highest frequencies (a water chiller is not included and may be supplied separately);
描述 [描述] operating wavelengths from 200 to 2700 nm