Propagation characteristics of a spatially chirped Gaussian laser beam propagating through multiple lenses
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Propagation characteristics of a spatially chirped Gaussian laser beam propagating through multiple lenses A. K. Sharma1,2 Received: 13 January 2020 / Accepted: 8 August 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Variation of curvature of laser beam changes characteristics of spatially chirped pulsed Gaussian (SCPG) laser beam primarily due to varying spectral divergence. Parametric dependence of different pulse parameters, e.g. angular chirp, pulse front tilt, pulse width, beam radius, radius of curvature etc., is presented for a SCPG laser beam propagating through single and pair of reflective or refractive optical system. Effect of chromatic aberration on characteristic of SCPG laser beam have also been presented under different propagation conditions. Different expressions for various parameters of pulsed Gaussian beam are extended using recursive relation for a sequence of multiple chromatic lenses generally used in large scale high energy high power laser system. Discussion is supported with few examples of lens system.
1 Introduction Energetic ultra-short laser pulses [1–10] are widely used to develop secondary sources of electromagnetic radiation (in range from THz to gamma-ray) [11–13] and particles (positive/negative charged and neutrals) [14–16] to curiosity driven research on laser matter interaction [17–20] for several scientific and industrial applications. Such laser pulses are generated using technique of chirped pulse amplification (CPA) [9] or optical chirped pulse amplification (OPCPA) [10], wherein an ultra-short laser pulse is first stretched in time, amplified in either single or multiplexed space time amplifier (laser or parametric) architecture [21] and then finally compressed in a Treacy like compressor [22]. In general, single or multiple dispersive optical elements are used in such laser schemes to obtain pulse width of compressed pulse comparable or smaller than that provided by femtosecond oscillator. Next, single lens or multiple lenses are also used in either pulse stretcher stage to achieve positive group delay dispersion or in between laser amplifiers of master oscillator power amplification (MOPA) scheme to avoid role of diffraction and non-linearity [23, 24] in a long haul laser
* A. K. Sharma [email protected] 1
Laser Technology Division, Raja Ramanna Centre for Advanced Technology, Indore 452013, India
Homi Bhabha National Institute, Mumbai 400094, India
2
systems such as VULCAN PW laser system [1], ORION laser system [5] in UK, Sandia Z-PW laser system [2], Texas PW hybrid laser system [3], Advanced Radiographic Capability on National Ignition Facility [4] in USA, and two beam Nd:phosphate glass based high energy high power hybrid laser system [6] at RRCAT Indore in India. While varying spectral divergence (also known as angular chirp or angular dispersion) change different parameters [25–38] of a spatially chirped laser beam, it is expected that characteristic of a spatially chirped (SC) laser beam should vary differently for pl
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