[2] S. Andersson-Engels, R. Berg, O. Jarlman, and S. Svanberg: Time-resolved transillumination for medical diagnostics, Optics Letters 15, 1179 (1990).
[3] S. Svanberg: Some applications of ultrashort laser pulses in biology and medicine, Meas. Sci. Technology 12, 1777 (2001).

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Cairo University

MTPR Journal

 

GENERATION OF A HIGH POWER TUNABLE ULTRAFAST WHITE LIGHT LASER FOR MEDICAL APPLICATIONS

2019-04-22
Walid Tawfik
National Institute of Laser enhanced sciences NILES, Cairo University, Cairo, Egypt
Vol./Issue: 19 , id: 256

In this work, the generation of widely tunable ultrafast high-power laser system with pulse duration of a few-cycle fs pulses using a nonlinear laser interaction in neon-filled hollow-core fiber is demonstrated. The seed source is a 15-fs mode-locked Ti: sapphire of 400 mW and 75 MHz at 800 nm working in TEM00 mode. In this system, the amplification was done via a 1 KHz CPA regenerative-amplifier which produced 32 fs pulses of 2.5 mJ at 800 nm. Then output pulses were highly-compressed by self-phase modulation in an inert gas as a nonlinear medium through a one-meter hollow optical fiber. The dispersion compensation of these pulses was done via a pair of chirped mirrors. The observed pulses have controlled durations from almost 4 fs to <10 fs with power 0.1 TW and repetition rate 1 KHz as shown in fig.1. The characterization of ultrafast pulses in the regime of few-cycle pulses is considered using spectral phase interferometry for direct electric-field reconstruction (SPIDER) [1]. These pulses can be tuned from about 12 to 94 THz by varying the chirping of input pulses at different pressure of the inert gas. The observed results can give an opportunity to control the progression of strongelectric- field interactions on the ultrafast time scale and can be applied to regenerate attosecond pulses in the deep ultraviolet range. The observed results may give an opportunity to controlling the progression of strong-electric-field interactions on the ultrafast time scale and are crucial to regenerate attosecond x-ray pulses. Furthermore, the generated ultrafast laser pluses can be utilized in many applications in medicine and biology. Obvious areas of utilization include time-resolved imaging and fluorescence spectroscopy. Such investigations can be applied in cases involving tissue examination in the cardiovascular sector as well as applications within the field of malignant diseases [2], [3]. Fig. The Temporal Profile of output

References:
[1] Tawfik, Walid. "Precise measurement of ultrafast laser pulses using spectral phase interferometry for direct electric-field reconstruction." Journal of Nonlinear Optical Physics & Materials 24.04 (2015): 1550040.
[2] S. Andersson-Engels, R. Berg, O. Jarlman, and S. Svanberg: Time-resolved transillumination for medical diagnostics, Optics Letters 15, 1179 (1990).
[3] S. Svanberg: Some applications of ultrashort laser pulses in biology and medicine, Meas. Sci. Technology 12, 1777 (2001).