DKDP crystal plasma pole Pockels cell driven by single pulse

Abstract

The invention provides a DKDP crystal plasma pole Pockels cell driven by a single pulse. A non-inductive capacitor is arranged in a DKDP crystal plasma pole Pockels cell driven by a single pulse, and the Pockels effect of a DKDP crystal driven by the single high-voltage switch pulse is realized. The DKDP crystal plasma pole Pockels cell driven by the single pulse has small discharging current, large diameter, low light absorption coefficient and stable puncture and can be used for the Q switch and stage isolation of a laser with large diameter and high average power.

Description

technical field [0001] The invention belongs to the field of high average power lasers, in particular to a single-pulse-driven DKDP crystal plasma electrode Pockels cell. Background technique [0002] In high average power lasers, in order to obtain high-power repetition rate laser pulses, a repetition rate Pockels cell is usually used for Q-switching and isolation. Under the high average power light load, the Pockels cell switch crystal will cause temperature rise and temperature gradient due to light absorption, which will change the refractive index and cause thermal depolarization and wavefront distortion of the transmitted beam. Therefore, switching crystals for high average power require a small linear absorption coefficient and a large thermal conductivity. [0003] Electro-optic crystals used for high average power Q-switching in recent years include: LiNbO 3 , BBO, KTP, RTP and DKDP. LiNbO 3 The absorption coefficient is low (~0.1% cm -1 ), but the electro-opti...

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Problems solved by technology

[0007] Article titled "26cm×26cm aperture plasma electrode electro-optic switch" (Henesian MA and GoldharJ, Demonstration of electro-optical switching at the 26cm×26cm aperture using plasma electrodes, Optics Letters, 1984, 9(11): 516~518) And the article titled "A simple method for the operation of the plasma-electrode Pockels cell of a megajoule laser device" (J. Gardelle, E. Pasini, B. Bicrel, A new regime of plasma-electrode Pockels cell operation for the laser megajoules project[ R], Proceeding of IFSA, 2001, 510~513) respectively disclose the plasma electrode Pockels cell of the above two working modes, but the existing two working modes of the plasma electrode Pockels cell are used in high average power applications has its limitations

In the traditional plasma electrode Pockels cell (PEPC) working mode, the high-current gas discharge time is maintained at tens or even hundreds of milliseconds, and the long-term discharge makes the gas ions continuously bombard the discharge cathode, which causes the temperature of the cathode to rise. , and then heat the switch crystal, causing optical thermal distortion and affecting the output of the laser

The single-pulse drive method (OPP) relies on positive and negative pulse high voltages to cause field breakdown of the working gas, thereby forming high-conductivity plasma and charging the Pockels cell, so a high half-wave voltage is used. KDP crystal, the advantage of this working method is that the discharge current is small and will not cause the temperature of the electrode to rise, but the KDP crystal has a large light absorption coefficient (~6%cm -1 ), thermal distortion is obvious, not suitable for application under high average power conditions

The light absorption coefficient of DKDP crystal is an order of magnitude smaller than that of KDP crystal, which can be applied under high average power conditions. However, the half-wave voltage of DKDP crystal is low. Under this voltage, the breakdown of the gas in the discharge chamber is unstable, and it is difficult to form an effective high conductivity plasma, making it difficult to achieve high switching efficiency

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