Complex Imaging Reflectometry for Dopant Profile Measurements using Tabletop High Harmonic Light

We report a theoretical investigation and elucidation of the x-ray absorption spectra of neutral benzene and of the benzene cation. The generation of the cation by multiphoton ultraviolet (UV) ionization as well as the measurement of<br>the carbon K-edge spectra of both species using a table-top high-harmonic generation (HHG) source are described in the companion experimental paper [M. Epshtein et al., J. Phys.<br>Chem. A., submitted. Available on ChemRxiv]. We show that the 1sC -> pi transition serves as a sensitive signature of the transient cation formation, as it occurs outside of the spectral window of the parent neutral species. Moreover, the presence<br>of the unpaired (spectator) electron in the pi-subshell of the cation and the high symmetry of the system result in significant differences relative to neutral benzene in the spectral features associated with the 1sC ->pi* transitions. High-level calculations using equation-of-motion coupled-cluster theory provide the interpretation of the experimental spectra and insight into the electronic structure of benzene and its cation.<br>The prominent split structure of the 1sC -> pi* band of the cation is attributed to the interplay between the coupling of the core -> pi* excitation with the unpaired electron<br>in the pi-subshell and the Jahn-Teller distortion. The calculations attribute most of<br>the splitting (~1-1.2 eV) to the spin coupling, which is visible already at the Franck-Condon structure, and estimate the additional splitting due to structural relaxation to<br>be around ~0.1-0.2 eV. These results suggest that x-ray absorption with increased resolution might be able to disentangle electronic and structural aspects of the Jahn-Teller<br>effect in benzene cation.<br>

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Generalized Heterodyne Configurations for Photo-induced Force Microscopy

10.26434/chemrxiv.9633407 ◽

2019 ◽

Author(s):

Le Wang ◽

Devon Jakob ◽

Haomin Wang ◽

Alexis Apostolos ◽

Marcos M. Pires ◽

...

Keyword(s):

Spatial Resolution ◽

Repetition Rate ◽

Modulation Frequency ◽

High Harmonic ◽

Chemical Imaging ◽

Heterodyne Detection ◽

Force Microscopy ◽

Wide Range ◽

The Difference ◽

Afm Cantilever

<div>Infrared chemical microscopy through mechanical probing of light-matter interactions by atomic force microscopy (AFM) bypasses the diffraction limit. One increasingly popular technique is photo-induced force microscopy (PiFM), which utilizes the mechanical heterodyne signal detection between cantilever mechanical resonant oscillations and the photo induced force from light-matter interaction. So far, photo induced force microscopy has been operated in only one heterodyne configuration. In this article, we generalize heterodyne configurations of photoinduced force microscopy by introducing two new schemes: harmonic heterodyne detection and sequential heterodyne detection. In harmonic heterodyne detection, the laser repetition rate matches integer fractions of the difference between the two mechanical resonant modes of the AFM cantilever. The high harmonic of the beating from the photothermal expansion mixes with the AFM cantilever oscillation to provide PiFM signal. In sequential heterodyne detection, the combination of the repetition rate of laser pulses and polarization modulation frequency matches the difference between two AFM mechanical modes, leading to detectable PiFM signals. These two generalized heterodyne configurations for photo induced force microscopy deliver new avenues for chemical imaging and broadband spectroscopy at ~10 nm spatial resolution. They are suitable for a wide range of heterogeneous materials across various disciplines: from structured polymer film, polaritonic boron nitride materials, to isolated bacterial peptidoglycan cell walls. The generalized heterodyne configurations introduce flexibility for the implementation of PiFM and related tapping mode AFM-IR, and provide possibilities for additional modulation channel in PiFM for targeted signal extraction with nanoscale spatial resolution.</div>

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The Novel Dopant Profile Inspection Methodology by FIB

ISTFA 2010: Conference Proceedings from the 36th International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa2010p0257 ◽

2010 ◽

Author(s):

Po Fu Chou ◽

Li Ming Lu

Keyword(s):

High Resolution ◽

Focused Ion Beam ◽

Ion Beam ◽

Real Sample ◽

Physical Analysis ◽

The Novel ◽

High Contrast ◽

Dopant Profile ◽

P Type

Abstract Dopant profile inspection is one of the focused ion beam (FIB) physical analysis applications. This paper presents a technique for characterizing P-V dopant regions in silicon by using a FIB methodology. This technique builds on published work for backside FIB navigation, in which n-well contrast is observed. The paper demonstrates that the technique can distinguish both n- and p-type dopant regions. The capability for imaging real sample dopant regions on current fabricated devices is also demonstrated. SEM DC and FIB DC are complementary methodologies for the inspection of dopants. The advantage of the SEM DC method is high resolution and the advantage of FIB DC methodology is high contrast, especially evident in a deep N-well region.

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High-harmonic generation in Su-Schrieffer-Heeger chains

Physical Review B ◽

10.1103/physrevb.99.195428 ◽

2019 ◽

Vol 99 (19) ◽

Cited By ~ 12

Author(s):

Christoph Jürß ◽

Dieter Bauer

Keyword(s):

Harmonic Generation ◽

High Harmonic ◽

High Harmonic Generation

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Picosecond Development of High Harmonic Emission from Co2 Laser-Produced Plasmas

IEEE Transactions on Plasma Science ◽

10.1109/tps.1979.4317224 ◽

1979 ◽

Vol 7 (3) ◽

pp. 166-170 ◽

Cited By ~ 9

Author(s):

P. A. Jaanimagi ◽

G. D. Enright ◽

M. C. Richardson

Keyword(s):

Co2 Laser ◽

High Harmonic ◽

Harmonic Emission

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High Field Single- to Few-Cycle THz Generation with Lithium Niobate

Photonics ◽

10.3390/photonics8060183 ◽

2021 ◽

Vol 8 (6) ◽

pp. 183

Author(s):

Xing Zhu ◽

David R. Bacon ◽

Julien Madéo ◽

Keshav M. Dani

Keyword(s):

Lithium Niobate ◽

Condensed Matter ◽

High Harmonic ◽

Nonlinear Spectroscopy ◽

Optical Rectification ◽

Phase Matching ◽

Nonlinear Phenomena ◽

Generation Efficiency ◽

Basic Principles ◽

Thz Generation

The transient terahertz (THz) pulse with high peak field has become an important tool for matter manipulation, enabling many applications such as nonlinear spectroscopy, particle acceleration, and high harmonic generation. Among the widely used THz generation techniques, optical rectification in lithium niobate (LN) has emerged as a powerful method to achieve high fields at low THz frequencies, suitable to exploring novel nonlinear phenomena in condensed matter systems. In this review, we focus on introducing single- to few-cycle THz generation in LN, including the basic principles, techniques, latest developments, and current limitations. We will first discuss the phase matching requirements of LN, which leads to Cherenkov-like radiation, and the tilted pulse front (TPF) technique. Emphasis will be put on the TPF technique, which has been shown to improve THz generation efficiency, but still has many limitations. Different geometries used to produce continuous and discrete TPF will be systematically discussed. We summarize the advantages and limitations of current techniques and future trends.

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