Journal Article

PUBDB-2023-01892

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Impact of pump beam spot size on semiconductor carrier dynamics in optical-pump-terahertz-probe spectroscopy

Staechelin, Y. (Corresponding author)CFEL*Extern* ; Kroh, T.CFEL*Extern* ; Kärtner, F.CFEL*XFEL.EU*DESY* ; Lange, H.Extern*XFEL.EU*

2023
Optica Washington, DC

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Please use a persistent id in citations: doi:10.1364/JOSAB.496228  doi:10.3204/PUBDB-2023-01892

Abstract: Optical-Pump-Terahertz-Probe experiments (OPTP) are widely employed to studythe dynamics of photoexcited carriers in semiconductors. In these experiments, due to the longwavelength nature of the Terahertz (THz) probe radiation, the probe beam can only be focused toa spot size in the mm range. To ensure homogeneous excitation of the probed sample region, asignificantly larger optical pump beam spot size must be used, which is often difficult to implementin the experiment. Frequently used experiment geometries employ beam paths which result in small pump beam spot sizes, leading to spectral distortions of the sample response, translating touncertainties in calculated THz conductivities and fitted Drude conductivity models, for example.We investigate the influence of the pump beam spot size on benchmark OPTP experiments andevaluate model calculations to estimate the induced deviations. We can demonstrate the impactof this effect on the acquired data with different dependencies on the investigated sample andthe employed experimental configuration. This way, we can provide guidelines for optimal configurations for the most commonly employed experiments.

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Contributing Institute(s):

1. Ultrafast Lasers & X-rays Division (FS-CFEL-2)

Research Program(s):

1. 631 - Matter – Dynamics, Mechanisms and Control (POF4-631) (POF4-631)
2. AXSIS - Frontiers in Attosecond X-ray Science: Imaging and Spectroscopy (609920) (609920)
3. DFG project 390715994 - EXC 2056: CUI: Advanced Imaging of Matter (390715994) (390715994)

Experiment(s):

1. AXSIS: Frontiers in Attosecond X-ray Science, Imaging and Spectroscopy
2. Experiments at CFEL

Appears in the scientific report 2023

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Database coverage:
; ; Clarivate Analytics Master Journal List ; Current Contents - Engineering, Computing and Technology ; Current Contents - Physical, Chemical and Earth Sciences ; Essential Science Indicators ; IF < 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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