Often ultrashort laser pulses of significantly higher energy than mode-locked laser pulses e. The voltage is applied to or removed from the Pockels cell 22 by operating the first and second switches S 1 B and S 1 A and likewise the third and fourth switches S 2 B and S 2 A in a push-pull manner, such as by simultaneously closing switch S 1 B and opening switch S 1 A, simultaneously closing switch S 1 A and opening switch S 1 B, or by simultaneously closing switch S 2 B and opening switch S 2 A, simultaneously closing switch S 2 A and opening switch S 2 B. The voltage is applied to the Pockels cell 22 by closing switch S 1 B and opening switch S 1 A first trigger signal 14 a and the voltage is removed from the Pockels cell 22 by applying the second trigger signal 14 b to the third and fourth switches S 2 B and S 2 A. The Pockels cell system 10 e includes a delay unit 13 e and a high voltage switching unit 11 e and is operated in a way analogous to FIG. A laser system with a short or ultrashort pulse laser and an external electro-optical modulator as disclosed herein can be used to do material processing with individually set and controlled laser pulses. It has been designed for high noise immunity and optimum signal integrity.
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In many cases, this Pockels cell system can enable pickels determined amplitudes of individual laser pulses in a pulse train of laser pulses. These two elements Pockels cell and analyzer together form the electro-optical modulator.
DE A1, the contents of which are incorporated herein by reference.
Since the polarizer 4 b can never be perfect, before the amplified pulse is extracted from the resonator, there will be a pulse train of pre-pulses leaking through this polarizer, with each amplified pulse reflected back. Year of fee payment: This improves upon some known Pockels cell systems by providing means for modifying the switching time when the high voltage is applied to celp Pockels cell.
Any number of these four control signals can have variable delays controlled by variable analog signals 15 a and 15 b fed to the delay units 13 and 23while the trigger signals 14 a and 14 b fixed delays.
Pockels Cell Drivers
The driver circuit 10 was operated such that the opening time of the Pockels cell CP, that is cel, say the time period between the closing of the first switching unit S 1 and the closing of the second switching unit S 2was 1.
A method for operating the laser system as claimed in claim 9wherein: Mass spectrometric analysis of surfaces. The first delay unit 13 receives a first trigger signal 14 a and generates control signals 17 a and 16 a applied to the first and second switches S 1 B and S 1 A.
This node is connected to a second potential, such as a ground terminal, via a second switch.
US20080018977A1 – Controlling pockels cells – Google Patents
As their main poockels, common electro-optical modulators use a Pockels cell with variable optical properties, and an element sensitive to the polarization direction of the light beam, such as a reflective analyzer with constant optical properties. The system of claim 8comprising a second delay unit, which is connected to the other of the first and second push-pull circuits, wherein the first and second delay units are controllable to generate different delays for their respective control signals.
The contents of the prior application are hereby incorporated by reference in their entirety. The Pockels cell 12 is likewise connected to the second potential P A.
Graph c of FIG. In order to measure the optical contrast of the Pockels cell CP during its opening time, a laser pulse having a time duration of 8 ns was drawn from a regenerative amplifier and the pulse of the Pockels cell CP was thus sampled.
The system of claim 10wherein time delay of control signals from the first delay unit is controlled by a first analog signal applied to the first delay unit, and wherein time delay of control signals from the second delay unit is controlled by a second analog signal, applied to the second delay unit.
CONTROLLING POCKELS CELLS – BME MESSGERAETE ENTWICKLUNG KG
As their main element, common electro-optical modulators use a Pockels cell with variable optical properties, and an element sensitive to the polarization direction of the light beam, such as a reflective analyzer with constant optical properties.
This alternating sequence is known from German Patent No. This can be done, for example, by measuring the energy of laser pulses when they leave the resonator or at some other location within the laser, comparing this value with some pocckels value, and shifting the voltage pulse applied to the Pockels cell cepl in time.
This well defined transmission versus time function will be applied synchronously with the impinging laser pulses to the Pockels cell, synchronous to every laser pulse, for example, to every second laser pulse or to every nth laser pulse. Furthermore, the regenerative amplifier comprises a pump light sourcefor example a laser diode array, and a lenswhich are arranged outside the resonator.
The switching unit 21 has a double push-pull circuit 21 including a first push-pull circuit 21 a and a second push-pull circuit 21 b. The time of the rising of falling edge of the voltage pulse may be positioned such as to achieve the desired amplitude of the transmitted laser pulse. The present application claims pocckels under 35 U.
BME – Bergmann Messgeraete Entwicklung: Pockels Cell Drivers
A rising edge of the high pocjels pulse is produced by simultaneously closing the first switch S 1 B and opening the second switch S 1 A, applying the high voltage to the Pockels cell The unwanted parts of the pulse train are reflected at polarizer 4 e into beam dump B, where they can be absorbed.
The time delays are controlled by analog signals 15 a and 15 b received to the delay units 13 and A method of producing short or ultrashort laser pulses of variable amplitude, the method comprising directing a pulse train of laser pulses towards the Pockels cell system of claim pocjels. Any desired intensity amplitude of pockeks transmitted laser pulse can then be attained by displacing the edge of the transmission versus time function with respect to the laser pulse.
A laser pulse is selected by the electro-optical modulator and is directed to a first output port of the electro-optical modulator. It has been designed for high noise immunity and optimum signal integrity.
pockesl Achieving large pressure gradients and at the same time not reducing the sensitivity of the mass spectrometer can be done by using gas flow restrictions with large cross sections. The polarization of the linear polarized laser pulse passing the Pockels cell is orthogonal to the orientation of the polarization selective element behind the Pockels cell, such that the laser pulse is not transmitted.
A laser system comprising a laser light source.