Publications by authors named "Achut Giree"

Noncollinear optical parametric amplifiers (NOPAs) have become the leading technique for the amplification of carrier-envelope phase (CEP)-stable, few-cycle pulses at high repetition rate and high average power. In this Letter, a NOPA operating at a repetition rate of 100 kHz delivering more than 24 W of average power before compression is reported. The amplified bandwidth supports sub-7 fs pulse durations and pulse compression close to the transform limit is realized.

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During amplification in a noncollinear optical parametric amplifier the spatial and temporal coordinates of the amplified field are inherently coupled. These couplings or distortions can limit the peak intensity, among other things. In this work, a numerical study of the spatiotemporal distortions in BBO-based noncollinear optical parametric chirped-pulse amplifiers (NOPCPAs) is presented for a wide range of parameters and for different amplification conditions.

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Non-collinear optical parametric amplification has become the leading technology for amplifying few-cycle carrier-envelope phase (CEP) stable pulses to high energy at extreme repetition rates. In this work, a parametric amplifier system devoted to ultrafast photoionization experiments with coincidence detection is reported. The amplifier delivers CEP-stable few-cycle pulses with an average power of 5 W, and operates at repetition rates between 400 and 800 kHz.

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We report on the generation of 34 fs and 50 µJ pulses from a high energy fiber amplifier system with nonlinear compression in an air-filled hypocycloid-core Kagome fiber. The unique properties of such fibers allow bridging the gap between solid core fibers-based and hollow capillary-based post-compression setups, thereby operating with pulse energies obtained with current state-of-the-art fiber systems. The overall transmission of the compression setup is over 70%.

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Coincident electron-ion detection after photoionization in a "reaction microscope" is a very powerful tool to study atomic and molecular dynamics. However, the implementation of this tool in the field of attosecond science has so far been rather limited, due to the lack of high repetition rate laser sources capable of delivering few-cycle pulses with sufficient energy per pulse. In this article, the development of a Non-collinear Optical Parametric Amplifier (NOPA) capable of delivering Carrier-Envelope Phase (CEP) stable pulses with sub-6 fs duration and pulse energies in the few-µJ range is presented.

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