Suitable for fs and ps Mode-locked Lasers
Acousto-Optical Single Pulse Selector
pulseSelect is an acousto-optical pulse picker, developed for the special demands of femtosecond laser technology. Pulse distortion is minimized by a low dispersive design and the use of reflective optics. High repetition rates and high contrast rates are achieved by using acousto-optical elements.
The pulse repetition rate can be reduced by an adjustable internal frequency divider or by external triggering. Pulse picking with low division ratios down to fREP/2 are possible. pulseSelect has an integrated RF power limitation and protection circuit to prevent modulator damage. For highest stability the phase of the RF carrier frequency is locked to the repetition rate of the laser in use.
At a Glance
- Reduction of the repetition rate of mode-locked lasers
- fs or ps mode-locked laser (e.g. Ti:Sapphire)
- Low dispersion design suitable for ultra-short pulses down to < 20 fs
- Division ratio continuously variable between fREP/2 … fREP/260,000
- Synchronized to laser seed with internal trigger
- Single-shot up to 3 MHz with external TTL trigger
- External trigger-gate mode
Single Stage Pulse Picker with pulseSelect
The Single pulseSelect consists of an optical module and control electronics. A Bragg cell represents the most important part of the optics, which selects individual pulses from the laser beam due to the acousto-optical effect. Focusing mirror, collimator mirror and a beam stop for the zero-order beam complete the setup. The driver electronics supplies the modulated RF signal for the Bragg cell with a carrier frequency that corresponds to the multiple of the laser repetition rate.
Double Stage Pulse Picker with Dual pulseSelect
Dual pulseSelect is available in two variants, Serial and Parallel. The Serial variant offers an improved contrast ratio of over 6000:1. The Parallel version allows the simultaneous picking of pulses from two synchronized laser sources.
Dual pulseSelect Serial: This version is designed to allow for highest contrast ratio of above 6000:1 by placing two Bragg cells. Both are synchronized to one common clock (in serial configuration; i.e. one beam through two Bragg cells).
Dual pulseSelect Parallel: This variant is designed for simultaneous picking of pulses from two synchronized laser sources. The system is equipped with two synchronized Bragg cells. Independent picking settings are possible for both Bragg cells.
Specifications
| pulseSelect Specification | ||||
|---|---|---|---|---|
| Broadband | High Power | High Power Dualband | ||
| Wavelength Ranges | 500 ... 1600 nm | 680 ... 1080 nm | 340 ... 540 nm + 680 ... 1080 nm | |
| Other ranges on request | Other ranges on request | Other ranges on request | ||
| Max. Laser Input Power | 2 W (SiO2) 0.5 W (TeO2) | < 5 W (SiO2) | < 5 W (SiO2) | |
| Diffraction Efficiency | > 50 % (SiO2) > 60% (TeO2) | > 50 % (SiO2) | > 50 % (SiO2) | |
| Contrast Ratio | > 500 : 1 for non-adjacent pulses, > 75 : 1 for main pulse to adjacent pulses (at 800 nm, fREP/20) | |||
| Input Frequency (fREP) (to be specified with 0.5 MHz accuracy at time of order) | 72 ... 81 MHz | |||
| Extended Input Frequency (only optionally) | 35 ... 90 MHz | |||
| External Trigger | Single-shot up to 3 MHz input | |||
| Input Polarization | Horizontal (polarization rotator optional) | |||
| Division Ratio | fREP/2 ... fREP/260,000 or externally triggered | |||
* These values depend on the laser spot diameter in the crystal or mirror coating and thus apply only to a certain system configuration. Please consult our technical staff to determine the maximum input power level as well as the appropriate focusing for the beam parameters applicable for your laser system setup.
** Ratio of the diffracted pulse energy to the pulse energy incident into Bragg cell. Measured with a fast photodiode at 800 nm and division ratio fREP/20. At division ratio fREP/2 the efficiency is typically around 25 % (TeO2) and around 10 % (SiO2), respectively.
*** > 500:1 applies for non-adjacent pulses. Main pulse to adjacent pulse contrast ratio is > 75:1 (@ 800 nm fREP/20)
| pulseSelect DUAL Specification | ||||
|---|---|---|---|---|
| Standard | HP-Ti:Sa | HP-Ti:Sa Dualband | ||
| Wavelength | 500 ... 1600 nm | 680 ... 1080 nm | 340 ... 540 nm and 680 ... 1080 nm | |
| Max. Input Power (PAV) | < 2 W (SiO2)* | < 5 W (SiO2)* | < 5 W (SiO2)* | |
| Input Frequency (to be specified with 0.5 MHz accuracy at time of order) | 72 ... 81 MHz | |||
| Extended Input Frequency (only optionally) | 35 ... 90 MHz | |||
| External Trigger | Single shot up to 3 MHz input | |||
| Input Polarization | Horizontal (polarization rotator optional) | |||
| Division Ratio | fREP/2 ... fREP/260,000 | |||
pulseSelect Dual (serial): | pulseSelect Dual (parallel): | |||
| Diffraction Efficiency | approx. 25 % (SiO2)** | > 50 % (SiO2)**/*** | ||
| approx. 36 % (TeO2)** | > 60 % (TeO2)**/*** | |||
| Contrast Ratio | > 6000:1**** | > 500:1***** |
* These values depend on the laser spot diameter in the crystal or mirror coating and for the type of Bragg cell indicated and thus apply only for a certain system configuration. Please consult our technical staff to determine the maximum input power level as well as the appropriate focussing for the beam parameters applicable for your laser system setup.
** Ratio of the diffracted pulse energy to the pulse energy incident into Bragg cell. Measured at 800 nm and division ratio fREP/20.
*** At division ratio fREP/2 the efficiency is typically around 25 % (TeO2 Bragg cell) and around 10 % (SiO2 Bragg cell), respectively.
**** Main pulse to adjacent pulse contrast ratio is > 6000:1 (@ 800 nm fREP/20)
***** > 500:1 applies for non-adjacent pulses. Main pulse to adjacent pulse contrast ratio is > 75:1 (@ 800 nm fREP/20)
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