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Pulse Pickers, Cavity Dumpers

Pulse Pickers, Cavity Dumpers

Pulse pickers and cavity dumpers are high speed acousto-optic modulators that can separate and divert a single laser pulse within a pulse train to a new optical path. Both require a very fast rise time with a low duty cycle. With rise/fall times as short as 4 ns and a variety of materials at our disposal, we can create a complete solution to select individual laser pulses with speed and synchronization.

腔腔专题指在氩气,染料或Ti:蓝宝石模式锁定激光器内部使用的声光调制器。脉冲拾取器在外部使用时描述了相同的功能。两者都使用高速声光晶体和设计技术将时间保持在最低限度。类似于快速调制器,需要在设备内的梁的紧密聚焦以实现所需的速度(通常上升时间是从脉冲激光选择单个脉冲时的主要选择标准。我们提供熔融二氧化硅,二氧化碲的材料选择(Teo.2), and gallium arsenide (GaAs) to achieve rise times of < 7 ns for wavelengths from the near-UV (350 nm) to the near infrared (1550 nm).

Other requirements which may require trade-off decisions include:

  • Optical power
  • 期望的吞吐量
  • Polarization of the input light (linear, circular, random)
  • Repetition rate of the laser
  • Pick rate required

尽管速度快,但脉冲拾取器或腔腔的调制率实际上是低(通常<10MHz)。声光器件在短时间内“开启”,然后是长时间的“关闭”时间。它专门设计用于最大化衍射效率,并在低占空比下操作时最小化上升/下降时间,但是只能为所需的有限时间处理高RF功率。

Optical power handling is a very important selection criteria for a pulse picker or cavity dumper. The rise time is limited by the time needed for the acoustic wave to travel through the optical beam. Tight focusing into the device is essential. This results in very high input power density. Our high manufacturing standards and rigorous adherence to quality of AO materials reduces scatter and results in industry-leading optical power handling. Where applicable, antireflection coatings minimize insertion loss.
By using a high RF carrier frequency and an optimized lens design, we can provide large angular separation between the undeflected and deflected beams (up to 75 mrad). This makes it easy to separate the two beams in space and maintain a static contrast ratio of at least 500:1.
The choice and application of the RF driver is particularly important in pulse picking and cavity dumping to synchronize accurately with the laser pulse train. Controls on the driver optimize the RF drive pulse shape and delay. The modulation signal is synchronized and optimized using a control loop to select the best time at which to pick off the pulse.

Synchronization of a pulse picker or cavity dumper can be quite complex, as can achieving the stringent focusing required to achieve high speeds. Our team can provide guidance in selecting the optimal combination of device and RF drivers.

Applications of Pulse Pickers, Cavity Dumpers

Generation of high energy pulses, injection and extraction of pulses from regenerative amplifiers, femtosecond/picosecond lasers, reduction of pulse repetition rates


Product Type Wavelength Rise / Fall Time Active Aperture Operating Frequency Optical Material