A5062557801- Thermography and Photoacoustic Techniques
- Ultrasonics and Acoustic Wave Propagation
- Photoacoustic and Ultrasonic Imaging
- Laser-Matter Interactions and Applications
- Advanced Fiber Optic Sensors
- Laser Material Processing Techniques
- Advanced MEMS and NEMS Technologies
- Advanced Electron Microscopy Techniques and Applications
- Force Microscopy Techniques and Applications
- Seismic Waves and Analysis
- Light effects on plants
- Optical Coatings and Gratings
- Photonic Crystal and Fiber Optics
- Laser Design and Applications
- Advanced Fiber Laser Technologies
- Spectroscopy and Quantum Chemical Studies
ASML (Netherlands)
2024
University of Amsterdam
2018-2021
Advanced Research Center for Nanolithography (Netherlands)
2018-2021
Tata Institute of Fundamental Research
2015
We investigate the spatial characteristics of high-order harmonic radiation generated in argon and observe cross-like patterns far field. An analytical model describing harmonics from an astigmatic driving beam reveals that these result order generation position-dependent divergence harmonics. Even small amounts field astigmatism may patterns, coming superposition individual with profiles elongated different directions. By correcting aberrations using a deformable mirror, we show fine-tuning...
A thorough understanding of the electron-phonon, thermo-optic, and acoustic properties materials is paramount importance for many applications in science advanced adopting laser-induced sound waves. Even though metals are usually opaque to light, optical methods characterization can still be developed, especially high-frequency regime, where phonon dynamics governs thermal, acoustic, even metals. Ultrafast laser pulses incident on lead generation coherent wave packets with frequencies...
We report on the detection of diffraction gratings buried below a stack tens 18-nm-thick ${\mathrm{Si}\mathrm{O}}_{2}$ and ${\mathrm{Si}}_{3}{\mathrm{N}}_{4}$ layers an optically opaque metal layer, using laser-induced, extremely high-frequency ultrasound. In our experiments, shape amplitude grating are encoded spatial phase reflected acoustic wave. This grating-shaped reflection is detected by delayed probe pulse. A detailed understanding measurements essential for nanometrology...
We report on femtosecond optical pump-probe measurements of ultrafast electron dynamics to detect the presence gratings buried underneath optically opaque gold layers. Electron energy diffusion and cooling are found be strongly affected by type metal below layer. As a result, spatially periodic grating is encoded temperature near top surface, leading modulation properties surface from which delayed probe pulse can diffracted. Our show that these effects may useful for detection alignment...
Filamentation and supercontinuum (SC) generation occur in transparent media during the propagation of intense femtosecond laser pulses. We report experimental results polarization-dependent SC third harmonic (THG) air using 40 fs, 800 nm pulses under varying focusing conditions. observe that tight enhances extent compared to when there is weak external focusing. Moreover, we incident beam linearly polarized yield more than obtained circularly light same energy, but this difference reduces as...
We present a high-resolution microscope capable of imaging buried structures through optically opaque materials with micrometer transverse resolution and nanometer-scale depth sensitivity. The ability to image such is made possible by the use laser ultrasonic techniques, where an ultrafast pulse launches acoustic waves inside layer subsequent echoes from interfaces are detected time-delayed probe pulse. show that high frequency generated ultrasound enables only limited optical detection...
Ultrafast laser-induced guided acoustic waves in thin, freely suspended films are important for many applications adopting the laser-ultrasonics technique. These show unique dispersion relations, leading to minimal propagation losses and energy confinement. While this principle has been known, separation of various physical effects formation measured signals involving these not clearly elaborated. Here, we present a combined experimental theoretical study on all-optical excitation detection...
We report on the use of ultra-high frequency photoacoustics to detect gratings with linewidths as narrow 75 nm, buried underneath optically opaque metal layers. Our results show that can be detected by observing diffraction from spatially periodic acoustic replica grating at glass/metal interface and replicas wave inside glass substrate. The measured signals a linear dependence duty cycle rather than expected quadratic one. find this is due presence coherent background optical field, which...
We present an experimental study in which we compare two different pump-probe setups to generate and detect high-frequency laser-induced ultrasound for the detection of gratings buried underneath optically opaque metal layers. One system is built around a high-fluence, low-repetition-rate femtosecond laser (1 kHz) other low-fluence, high-repetition-rate (5.1 MHz). find that signal diffracted by acoustic replica grating as function time delay very used. attribute this difference presence...
We report on the use of laser-induced ultrasonics for detection gratings with amplitudes as small 0.5 nm, buried underneath an optically opaque nickel layer. In our experiments, we fabricated top a layer glass, and pump probe sample from glass side. The diffraction pulse acoustic echo grating is measured function time. numerical model to show how various physical phenomena such interface displacement, strain-optic effects, thermo-optic surface roughness influence shape strength...
Light-induced acoustic waves can be used as sensitive probes, providing a pathway toward microscopic imaging and metrology in optically inaccessible media. The ability to detect such depends on the interaction of an optical probe pulse with topmost layers structure. Therefore, interplay between optoacoustic coupling material boundaries, combined properties near free surfaces is prime importance. Here we show approach optimized detection laser-excited waves. We explore physics underlying this...
Ultrafast laser pulses incident on metals can lead to the generation of coherent phonon wave packets with frequencies in gigahertz terahertz range [1,2]. Material characterization using such ultrafast laser-induced ultrasound provides access a frequency that is inaccessible by any other means. Our objective study optical and acoustic properties materials generating detecting waves pulses. To generate high way also optimizes their detection, we use pair crossed 40 fs femtosecond pump at 400...
We investigate the spatial characteristics of high-order harmonic radiation generated in argon, and observe cross-like patterns far field. An analytical model describing harmonics from an astigmatic driving beam reveals that these result order generation position dependent divergence harmonics. Even small amounts field astigmatism may patterns, coming superposition individual with profiles elongated different directions. By correcting aberrations using a deformable mirror, we show...