Pockels cell driver
First Claim
1. A Pockels cell driver which comprises a vacuum tube having a cathode, a grid and an anode, a resistor connecting said anode to a source of voltage at least as high as the half wavelength voltage of the Pockels cell, a storage capacitor connecting the anode to one end of the Pockels cell, means connecting the other end of the Pockels cell to the cathode of said tube, and means connected to the grid of said tube for switching said tube into conduction for a period of time sufficient to discharge said storage capacitor and to charge the capacitance presented by the Pockels cell to increase the voltage across the Pockels cell at least to the half wavelength voltage thereof.
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Accused Products
Abstract
A Pockels cell driver useful to operate the Pockels cell as an optical shutter to select one or more laser pulses out of a train of laser pulses when the Pockels cell is placed between crossed polarizers. The Pockels cell is connected through a storage capacitor, of higher capacitance than the capacitance of the Pockels cell, directly to a high voltage source and is charged to high voltage. The cell is charged and the storage capacitor is discharged through a microwave triode which is triggered by an avalanche transistor switch circuit. By directly charging the Pockels cell, lower currents are used than with conventional Pockels cell drivers using transmission lines to connect to the Pockels cell and gas filled tubes to switch a pulse-forming line. The Pockels cell shutter can be operated to provide transmission intervals for the laser pulses of the order of a nanosecond at high repetition rates, up to 10 KHz, without jitter in the timing of the transmission interval and for long periods of time without frequent need for replacement of the microwave triode.
21 Citations
15 Claims
- 1. A Pockels cell driver which comprises a vacuum tube having a cathode, a grid and an anode, a resistor connecting said anode to a source of voltage at least as high as the half wavelength voltage of the Pockels cell, a storage capacitor connecting the anode to one end of the Pockels cell, means connecting the other end of the Pockels cell to the cathode of said tube, and means connected to the grid of said tube for switching said tube into conduction for a period of time sufficient to discharge said storage capacitor and to charge the capacitance presented by the Pockels cell to increase the voltage across the Pockels cell at least to the half wavelength voltage thereof.
- 13. Pockels cell light transmission control apparatus which comprises a Pockels cell having a capacitance and internal resistance defining a first time constant, a resistor and a capacitor connecting said cell to a source of voltage sufficient to render said cell transmissive to a certain polarization of light, said resistor and capacitor presenting a time constant of the same order of magnitude as said cell and its internal resistance, and means connected between the junction of said resistor and capacitor and to complete a current path through said capacitor and said cell for discharging said capacitor and charging said cell.
Specification