Your cart is currently empty!
PhD in Physics — Overview
We generate a high temperature plasma by impacting a laser pulse onto a liquid metal target. Such plasma is an efficient light source, emitting extreme ultraviolet light. In industrial Nanolithography, this 13.5 nm light is used to pattern nano-scale transistors, enabling advanced computing and memory storage.
My PhD thesis can be found here.
Outstanding Efficiency
We achieve record light generation efficiencies for plasma produced using a solid-state laser. This may enable a greener way to manufacture computing chips.
By understanding the underlying physics of EUV (Extreme Ultraviolet 13.5 nm light) emitting plasma, we optimized its output to achieve record efficiencies. We use an in-house built 2 μm wavelength laser system to drive liquid tin droplets to plasma state. The resulting plasma emits EUV efficiently.
We find that the efficiency of light emission depends primarily on the incident laser intensity and spatio-temporal profile. A more uniform illumination maintains a uniform temperature plasma that emits more light. Larger and longer pulses result in a higher energy output.
“Physics is the science of matter & energy, and how they interact.”
– Phil Berneburg
Two Takeaways
Laser Layout
A flat laser beam profile, both across space and time, results in the most efficient generation of EUV light. This results from the fact that a uniform laser will heat and sustain the plasma evenly, thus maintaining the optimum temperature needed for light generation. A larger, slightly more intense laser beam with longer pulse duration may allow more energy to be extracted from the system at a minimal loss of efficiency.
Mass Matters
By studying the amount of liquid tin mass overlapping with the laser beam, we reach an important discovery.
The amount of mass you supply to the plasma determines its lifetime and efficiency. Put too little tin in, and the plasma will run out of mass and fail to sustain a high light emission efficiency. Adding more mass than necessary has no effect on the light emission efficiency but will cost more.
Mostafa, Yahia. (2019). Ordnung Muss Sein? Chromophoric Interactions in Photo-voltaic Conjugated Polymers.
Mostafa, Yahia. (2018). Thermal Simulations for the Target Station at FAIR.
Schlathölter, T., Mostafa, Y., Kamman, A., Dongelmans, A., Arribard, Y., Cazaux, S., & Hoekstra, R. (2020). Atomic hydrogen interactions with small polycyclic aromatic hydrocarbons cations. The European Physical Journal D, 74, 1–7.
Mostafa, Yahia. (2020a). Beyond Conventional Memory Storage: Multiferroics On the Rise.
Mostafa, Yahia. (2020b). Magnetic Properties of Strained BiFeO3 as Revealed by Magnetotransport Measurements and Atomistic Simulations.
Schupp, R., Behnke, L., Bouza, Z., Mazzotta, Z., Mostafa, Y., Lassise, A., … Ubachs, W. (2021). Characterization of angularly resolved EUV emission from 2-µm-wavelength laser-driven Sn plasmas using preformed liquid disk targets. Journal of Physics D: Applied Physics, 54(36), 365103.
Bouza, Z., Byers, J., Scheers, J., Schupp, R., Mostafa, Y., Behnke, L., … Hoekstra, R. (2021). The spectrum of a 1-μm-wavelength-driven tin microdroplet laser-produced plasma source in the 5.5–265.5 nm wavelength range. AIP Advances, 11(12).
Behnke, Lars, Schupp, R., Bouza, Z., Mostafa, Y., Lassise, A., Poirier, L., … Ubachs, W. (2021). Characterization of tin plasma driven by high-energy, 2-μm-wavelength light.
Poirier, L., Bayerle, A., Lassise, A., Torretti, F., Schupp, R., Behnke, L., … Hoekstra, R. (2022). Cross-calibration of a combined electrostatic and time-of-flight analyzer for energy-and charge-state-resolved spectrometry of tin laser-produced plasma. Applied Physics B, 128(3), 39.
Hernandez-Rueda, J., Liu, B., Hemminga, D. J., Mostafa, Y., Meijer, R. A., Kurilovich, D., … Versolato, O. O. (2022). Early-time hydrodynamic response of a tin droplet driven by laser-produced plasma. Physical Review Research, 4(1), 013142.
Versolato, O. O., Schupp, R., Behnke, L., Mostafa, Y., Bouza, Z., Lassise, A., … Ubachs, W. (2022). Solid-state-laser driven plasma produced from laser-preformed tin microdroplets for high-brightness EUV. ETh5A-7. Optica Publishing Group.
Behnke, Lars, Mostafa, Y., Schupp, R., Bouza, Z., Lassise, A., Bayraktar, M., … Versolato, O. O. (2022). Generation of 2-micrometer wavelength laser-light to drive euv-emitting plasmas. JW5A-8. Optica Publishing Group.
Poirier, L., Lassise, A., Mostafa, Y., Behnke, L., Braaksma, N., Assink, L., … Versolato, O. O. (2022). Energy-and charge-state-resolved spectrometry of tin laser-produced plasma using a retarding field energy analyzer. Applied Physics B, 128(7), 135.
Behnke, Lars, Mostafa, Y., Bouza, Z., Lassise, A., Poirier, L., Sheil, J., … Versolato, O. (2022). Two-micrometer-wavelength laser-produced tin plasma EUV sources. PC122920D. SPIE.
Mostafa, Y., Bouza, Z., Byers, J., Babenko, I., Ubachs, W., Versolato, O. O., & Bayraktar, M. (2023). Extreme ultraviolet broadband imaging spectrometer using dispersion-matched zone plates. Optics Letters, 48(16), 4316–4319.
Behnke, Lars, Salumbides, E. J., Göritz, G., Mostafa, Y., Engels, D., Ubachs, W., & Versolato, O. (2023). High-energy parametric oscillator and amplifier pulsed light source at 2-µm. Optics Express, 31(15), 24142–24156.
Mostafa, Y., Behnke, L., Engels, D. J., Bouza, Z., Sheil, J., Ubachs, W., & Versolato, O. O. (2023). Production of 13.5 nm light with 5% conversion efficiency from 2 μm laser-driven tin microdroplet plasma. Applied Physics Letters, 123(23).
Behnke, L., Mostafa, Y., Bouza, Z., Poirier, L., Lassise, A., Schupp, R., … Versolato, O. O. (2022). Investigation of tin plasma driven by high-energy 2-µm-wavelength light. European Physical Society.
Mostafa, Y., Behnke, L., Engels, D. J., Bouza, Z., Sheil, J., Ubachs, W., & Versolato, O. O. (2024). Highly Efficient 13.5 nm Light Generation Using 2 μm Laser Driven Tin Plasma. ETu5A-3. Optica Publishing Group.
de Lange, S. J. J., Hemminga, D. J., Mostafa, Y., Meijer, R. A., Versolato, O. O., & Sheil, J. (2024). Modeling the hundreds-of-nanoseconds-long irradiation of tin droplets with a 2 µm-wavelength laser for future EUV lithography. Plasma Sources Science and Technology, 33(10), 105003.
Babenko, I., Mostafa, Y., Bouza, Z., Versolato, O. O., & Bayraktar, M. (2024). Spectral and spatial resolution of an extreme ultraviolet broadband imaging spectrometer based on dispersion-matched zone plates. AIP Advances, 14(10).
Mostafa, Yahia. (2025). Mass & Energy Efficient Tin Laser Produced Plasma Light Sources.