Laser produced x-ray by high brightness and power diode pumped Nd:YAG laser for compact x-ray lithography and microscopy

High Brightness and Power Diode Pumped Nd:YAG Laser is the engine for Laser Produced X-ray (LPX). The LPX system consists of a compact diode pumped Nd:YAG laser system which produces brightness in excess of 10 15 W/cm 2 on target at up to 300 watts average power (4 parallel beams). The MOPA (Master Oscillator Power Amplifier) laser system delivers 250 mJ/pulse @ 300 Hz per beam (75 W average). 4 beams system at 300 W average power was demonstrated. The high brightness is achieved using ~800 ps pulse duration and near diffraction limited beam quality. Very high conversion efficiency (~9%) into 2π sr from 1064 nm laser output to 1 nm broadband x-ray was demonstrated using copper tape target. 1 nm x-rays were used for proximity x-ray lithography and demonstrated feature size resolution down to 75 nm. Narrow linewidth x-ray (λ/Δλ~600) has also been demonstrated with 1% conversion efficiency from 532 nm to 3.37 nm using Mylar tape target for compact high resolution and contrast x-ray tomography for biological cells. A unique mechanical shutter was developed to stop all the ablated debris from the target material that can damage and contaminate the fragile x-ray optics.