Wavefront-correction for nearly diffraction-limited focusing of dual-color laser beams to high intensities.

Baozhen Zhao,Chad Petersen,Jared Mills,Shouyuan Chen,Donald Umstadter,Sudeep Banerjee,Jun Zhang,Grigory Golovin,Kevin Brown,Cheng Liu

doi:10.1364/oe.22.026947

Abstract

We demonstrate wavefront correction of terawatt-peak-power laser beams at two distinct and well-separated wavelengths. Simultaneous near diffraction-limited focusability is achieved for both the fundamental (800 nm) and second harmonic (400 nm) of Ti:sapphire-amplified laser light. By comparing the relative effectiveness of various correction loops, the optimal ones are found. Simultaneous correction of both beams of different color relies on the linear proportionality between their wavefront aberrations. This method can enable two-color experiments at relativistic intensities.

Highlights

Laser beams with two different colors are often used simultaneously in conventional lowpower optical science and applications
We demonstrate wavefront correction of terawatt-peak-power laser beams at two distinct and well-separated wavelengths
By comparing the relative effectiveness of various correction loops, the optimal ones are found. Simultaneous correction of both beams of different color relies on the linear proportionality between their wavefront aberrations

Summary

Introduction

Laser beams with two different colors are often used simultaneously in conventional lowpower optical science and applications. This technique has been used with ultrahigh peak power lasers to study high field interactions of light with matter. For generating the two different colors, the standard approach is to use the fundamental frequency of laser light and its second-harmonic generated (SHG) frequency. The much higher intensity contrast of pulses of SHG light, as compared with pulses at the fundamental wavelength, reduces the detrimental effect of low-density plasma generated by the foot of the laser pulse. Yu et al proposed using two-color high-intensity laser pulses, the fundamental and second harmonic, from a Ti:sapphire CPA system to produce ultra-low emittance electron beams by means of laser wakefield acceleration [7]

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