Determining carrier envelope phase of ultra-short laser pulses comprises use of target stimulated by pulse to emit radiation which is detected and analyzed

摘要

A laser pulse (1) is directed onto a target. In the region of interaction between the pulse and target, a plasma is produced and electromagnetic radiation is emitted. This is registered by a detector and sent to an analysis unit determining the carrier envelope phase (4) of the laser pulse. Between a fraction of an oscillation and a few oscillations of the electromagnetic field of the laser pulse carrier wave (3), are included between the ends of the laser pulse (2). The laser pulse duration is 10-21 - 10-12 s. The laser pulse wavelength is 10-12 m to 10-3 m. Its energy is 5 mu J to 1500 mu J. An optical element in the path to the target, focuses or deflects the laser pulse. It focuses the beam onto the target, to a diameter of 0.01 mu m to 1000 mu m. The target is gaseous, e.g. air. It is alternatively a solid body. The detector determines the amplitude or polarity of the radiation emitted. It is optoelectronic. It includes an electro-optical crystal. The optoelectronic detector has a refractive index dependent on the electrical field acting upon it, especially on its polarity and field strength. A second optical element is positioned in the beam path, after the target. This re-focuses or deflects emitted radiation. A splitter produces a pulse incident on the target and a second pulse incident on the detector. Splitter dispersion is pre-compensated, minimizing pulse duration in the target interaction region. The second pulse is delayed for simultaneous pulse reception at the crystal. The detector has a polarizer testing second pulse polarization. The detector has a further delay element, especially a quarter wave delay plate. It includes a polarizing beam splitter. It includes two photodetectors. The analysis unit comprises a differential amplifier. It includes an analog-to-digital converter and a computer. An independent claim is included for the corresponding method.