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Li D, Liang W, Li D, Ji L, Yan B, Chang J, Xi T, Zhang L, Cai Y, Hao Z. Distinguishing the nonlinear propagation regimes of vortex femtosecond pulses in fused silica by evaluating the broadened spectrum. OPTICS EXPRESS 2023; 31:32752-32760. [PMID: 37859070 DOI: 10.1364/oe.497418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Accepted: 09/07/2023] [Indexed: 10/21/2023]
Abstract
The nonlinear propagation dynamics of vortex femtosecond laser pulses in optical media is a topic with significant importance in various fields, such as nonlinear optics, micromachining, light bullet generation, vortex air lasing, air waveguide and supercontinuum generation. However, how to distinguish the various regimes of nonlinear propagation of vortex femtosecond pulses remains challenging. This study presents a simple method for distinguishing the regimes of nonlinear propagation of femtosecond pulses in fused silica by evaluating the broadening of the laser spectrum as the input pulse power gradually increases. The linear, self-focusing and mature filamentation regimes for Gaussian and vortex femtosecond pulses in fused silica are distinguished. The critical powers for self-focusing and mature filamentation of both types of laser pulses are obtained. Our work provides a rapid and convenient method for distinguishing different regimes of nonlinear propagation and determining the critical powers for self-focusing and mature filamentation of Gaussian and structured laser pulses in optical media.
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Sakakura M, Lei Y, Wang L, Yu YH, Kazansky PG. Ultralow-loss geometric phase and polarization shaping by ultrafast laser writing in silica glass. LIGHT, SCIENCE & APPLICATIONS 2020; 9:15. [PMID: 32047624 PMCID: PMC7000703 DOI: 10.1038/s41377-020-0250-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 12/27/2019] [Accepted: 01/14/2020] [Indexed: 05/11/2023]
Abstract
Polarization and geometric phase shaping via a space-variant anisotropy has attracted considerable interest for fabrication of flat optical elements and generation of vector beams with applications in various areas of science and technology. Among the methods for anisotropy patterning, imprinting of self-assembled nanograting structures in silica glass by femtosecond laser writing is promising for the fabrication of space-variant birefringent optics with high thermal and chemical durability and high optical damage threshold. However, a drawback is the optical loss due to the light scattering by nanograting structures, which has limited the application. Here, we report a new type of ultrafast laser-induced modification in silica glass, which consists of randomly distributed nanopores elongated in the direction perpendicular to the polarization, providing controllable birefringent structures with transmittance as high as 99% in the visible and near-infrared ranges and >90% in the UV range down to 330 nm. The observed anisotropic nanoporous silica structures are fundamentally different from the femtosecond laser-induced nanogratings and conventional nanoporous silica. A mechanism of nanocavitation via interstitial oxygen generation mediated by multiphoton and avanlanche defect ionization is proposed. We demonstrate ultralow-loss geometrical phase optical elements, including geometrical phase prism and lens, and a vector beam convertor in silica glass.
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Affiliation(s)
- Masaaki Sakakura
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK
| | - Yuhao Lei
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK
| | - Lei Wang
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK
| | - Yan-Hao Yu
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK
| | - Peter G. Kazansky
- Optoelectronics Research Centre, University of Southampton, Southampton, SO17 1BJ UK
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Dai Y, Patel A, Song J, Beresna M, Kazansky PG. Void-nanograting transition by ultrashort laser pulse irradiation in silica glass. OPTICS EXPRESS 2016; 24:19344-19353. [PMID: 27557213 DOI: 10.1364/oe.24.019344] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The structural evolution from void modification to self-assembled nanogratings in fused silica is observed for moderate (NA > 0.4) focusing conditions. Void formation, appears before the geometrical focus after the initial few pulses and after subsequent irradiation, nanogratings gradually occur at the top of the induced structures. Nonlinear Schrödinger equation based simulations are conducted to simulate the laser fluence, intensity and electron density in the regions of modification. Comparing the experiment with simulations, the voids form due to cavitation in the regions where electron density exceeds 1020 cm-3 but is below critical. In this scenario, the energy absorption is insufficient to reach the critical electron density that was once assumed to occur in the regime of void formation and nanogratings, shedding light on the potential formation mechanism of nanogratings.
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Nomura W, Kawazoe T, Yatsui T, Naruse M, Ohtsu M. Observation and analysis of structural changes in fused silica by continuous irradiation with femtosecond laser light having an energy density below the laser-induced damage threshold. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2014; 5:1334-1340. [PMID: 25247116 PMCID: PMC4168768 DOI: 10.3762/bjnano.5.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 07/26/2014] [Indexed: 06/03/2023]
Abstract
The laser-induced damage threshold (LIDT) is widely used as an index for evaluating an optical component's resistance to laser light. However, a degradation in the performance of an optical component is also caused by continuous irradiation with laser light having an energy density below the LIDT. Therefore, here we focused on the degradation in performance of an optical component caused by continuous irradiation with femtosecond laser light having a low energy density, i.e., laser-induced degradation. We performed an in situ observation and analysis of an increase in scattering light intensity in fused silica substrates. In experiments conducted using a pulsed laser with a wavelength of 800 nm, a pulse width of 160 fs and pulse repetition rate of 1 kHz, we found that the scattered light intensity increased starting from a specific accumulated fluence, namely, that the laser-induced degradation had a threshold. We evaluated the threshold fluence F t as 6.27 J/cm(2) and 9.21 J/cm(2) for the fused silica substrates with surface roughnesses of 0.20 nm and 0.13 nm in R a value, respectively, showing that the threshold decreased as the surface roughness increased. In addition, we found that the reflected light spectrum changed as degradation proceeded. We analyzed the details of the degradation by measuring instantaneous reflectance changes with a pump-probe method; we observed an increase in the generation probability of photogenerated carriers in a degraded silica substrate and a damaged silica substrate and observed a Raman signal originating from a specific molecular structure of silica. From these findings, we concluded that compositional changes in the molecular structure occurred during degradation due to femtosecond laser irradiation having an energy density below the LIDT.
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Affiliation(s)
- Wataru Nomura
- School of Engineering, The University of Tokyo, and The Nanophotonics Research Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656 Japan
| | - Tadashi Kawazoe
- School of Engineering, The University of Tokyo, and The Nanophotonics Research Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656 Japan
| | - Takashi Yatsui
- School of Engineering, The University of Tokyo, and The Nanophotonics Research Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656 Japan
| | - Makoto Naruse
- National Institute of Information and Communications Technology, 4-2-1 Nukui-kita, Koganei, Tokyo 184-8795, Japan
| | - Motoichi Ohtsu
- School of Engineering, The University of Tokyo, and The Nanophotonics Research Center, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo, 113-8656 Japan
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Mermillod-Blondin A, Mauclair C, Bonse J, Stoian R, Audouard E, Rosenfeld A, Hertel IV. Time-resolved imaging of laser-induced refractive index changes in transparent media. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:033703. [PMID: 21456747 DOI: 10.1063/1.3527937] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We describe a method to visualize ultrafast laser-induced refractive index changes in transparent materials with a 310 fs impulse response and a submicrometer spatial resolution. The temporal profile of the laser excitation sequence can be arbitrarily set on the subpicosecond and picosecond time scales with a pulse shaping unit, allowing for complex laser excitation. Time-resolved phase contrast microscopy reveals the real part of the refractive index change and complementary time-resolved optical transmission microscopy measurements give access to the imaginary part of the refractive index in the irradiated region. A femtosecond laser source probes the complex refractive index changes from the excitation time up to 1 ns, and a frequency-doubled Nd:YAG laser emitting 1 ns duration pulses is employed for collecting data at longer time delays, when the evolution is slow. We demonstrate the performance of our setup by studying the energy relaxation in a fused silica sample after irradiation with a double pulse sequence. The excitation pulses are separated by 3 ps. Our results show two dimensional refractive index maps at different times from 200 fs to 100 μs after the laser excitation. On the subpicosecond time scale we have access to the spatial characteristics of the energy deposition into the sample. At longer times (800 ps), time-resolved phase contrast microscopy shows the appearance of a strong compression wave emitted from the excited region. On the microsecond time scale, we observe energy transfer outside the irradiated region.
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Affiliation(s)
- Alexandre Mermillod-Blondin
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Straße, D-12489 Berlin, Germany.
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Water Radiolysis: Influence of Oxide Surfaces on H2 Production under Ionizing Radiation. WATER 2011. [DOI: 10.3390/w3010235] [Citation(s) in RCA: 274] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Jing X, Shao J, Zhang J, Jin Y, He H, Fan Z. Calculation of femtosecond pulse laser induced damage threshold for broadband antireflective microstructure arrays. OPTICS EXPRESS 2009; 17:24137-24152. [PMID: 20052125 DOI: 10.1364/oe.17.024137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
In order to more exactly predict femtosecond pulse laser induced damage threshold, an accurate theoretical model taking into account photoionization, avalanche ionization and decay of electrons is proposed by comparing respectively several combined ionization models with the published experimental measurements. In addition, the transmittance property and the near-field distribution of the 'moth eye' broadband antireflective microstructure directly patterned into the substrate material as a function of the surface structure period and groove depth are performed by a rigorous Fourier model method. It is found that the near-field distribution is strongly dependent on the periodicity of surface structure for TE polarization, but for TM wave it is insensitive to the period. What's more, the femtosecond pulse laser damage threshold of the surface microstructure on the pulse duration taking into account the local maximum electric field enhancement was calculated using the proposed relatively accurate theoretical ionization model. For the longer incident wavelength of 1064 nm, the weak linear damage threshold on the pulse duration is shown, but there is a surprising oscillation peak of breakdown threshold as a function of the pulse duration for the shorter incident wavelength of 532 nm.
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Affiliation(s)
- Xufeng Jing
- Key Laboratory of Materials for High Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, PR China.
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Ismail-Beigi S, Louie SG. Self-trapped excitons in silicon dioxide: mechanism and properties. PHYSICAL REVIEW LETTERS 2005; 95:156401. [PMID: 16241743 DOI: 10.1103/physrevlett.95.156401] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2005] [Indexed: 05/05/2023]
Abstract
Irradiating silica produces self-trapped excitons (STEs) that spontaneously create atomic-scale distortions on which they localize themselves. Despite enduring interest in STEs and subsequent defects in this key technological material, the trapping mechanism and geometry remain a mystery. Our ab initio study of STEs in alpha-quartz using a many-electron Green's function approach answers both questions. The STE comprises a broken O-Si bond with the hole localized on the defected oxygen and the electron on the defected silicon atom in a planar sp2 conformation. The results further explain quantitatively the measured STE spectra.
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Affiliation(s)
- Sohrab Ismail-Beigi
- Department of Applied Physics, Yale University, New Haven, Connecticut 06520, USA
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Thomas JK. Physical Aspects of Radiation-Induced Processes on SiO2, γ-Al2O3, Zeolites, and Clays. Chem Rev 2005; 105:1683-734. [PMID: 15884787 DOI: 10.1021/cr020378a] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- J K Thomas
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, USA.
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Milosavljevic BH, Thomas JK. Reactions of Electrons on the Surface of γ-Al2O3. A Pulse Radiolytic Study with 0.4 MeV Electrons. J Phys Chem B 2003. [DOI: 10.1021/jp030348r] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- B. H. Milosavljevic
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
| | - J. K. Thomas
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556-5670
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Zhang G, Mao Y, Thomas JK. Surface Chemistry Induced by High Energy Radiation in Silica of Small Particle Structures. J Phys Chem B 1997. [DOI: 10.1021/jp971102n] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guohong Zhang
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - Yun Mao
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
| | - J. Kerry Thomas
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556
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Daguzan P, Martin P, Guizard S, Petite G. Electron relaxation in the conduction band of wide-band-gap oxides. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:17099-17105. [PMID: 9981135 DOI: 10.1103/physrevb.52.17099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Audebert P, Daguzan P, Gauthier JC, Geindre JP, Guizard S, Hamoniaux G, Krastev K, Martin P, Petite G, Antonetti A. Space-time observation of an electron gas in SiO2. PHYSICAL REVIEW LETTERS 1994; 73:1990-1993. [PMID: 10056940 DOI: 10.1103/physrevlett.73.1990] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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