Pulse shaping unit

Abstract

The present invention provides a pulse shaping device. It includes two grating, which can be used for separating lasers with different frequencies at an angle or combining them; two concave mirrors, which can be used for making conversion of time domain and frequency domain of laser pulse; and a light modulator, which is positioned in central position of first concave mirror and second concave mirror, and can be used for modulating amplitude or phase of laser pulse; and the distance between every two optical devices is identical fixed value so as to can obtain accurate Fourier transform of reflected light passed through said concave mirrors. Said light modulator is a liquid crystal space light modulator, it can utilize the change of voltage applied to liquid crystal to control arrangement of liquid crystal molecules to change refractivity of medium so as to regulate amplitude and phase of laser pulse.

Description

technical field [0001] The invention relates to a pulse shaping device, in particular to an ultrafast laser pulse shaping device. Background technique [0002] Laser pulse shaping technology is to generate the pulse waveform that people need by controlling the amplitude, phase and frequency of the pulse. At present, a zero-dispersion pulse shaping device with a 4F structure is commonly used in the field of laser pulse shaping technology. figure 1 It is an existing 4F structure zero-dispersion pulse shaping device, which includes a first grating and a second grating 10 , a first convex lens and a second convex lens 12 , and an optical modulator 16 . The first and second gratings are identical, as are the first and second convex lenses. Wherein, the light modulator 16 is located at the center of the first convex lens and the second convex lens 12 . The distance between each optical device is the focal length F of the convex lens, so the devic...

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Problems solved by technology

[0004] However, if the convex lens used in the prior art works well when the pulse width is large, when the pulse width is very narrow, the output pulse is not ideal due to the chromatic aberration caused by the lens.

In addition, fixed spatial mask optical modulators are generally used in the prior art, but this type of optical modulator cannot achieve continuous modulation of the optical phase, so a new optical modulator must be fabricated for each experiment

These shortcomings undoubtedly limit the application and development of the 4F structure, so we need a pulse shaping method and device that can avoid chromatic aberration and perform continuous optical phase modulation

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